diff --git a/homeassistant/components/kankun/switch.py b/homeassistant/components/kankun/switch.py
index 5d41b2360e9..63f289862f6 100644
--- a/homeassistant/components/kankun/switch.py
+++ b/homeassistant/components/kankun/switch.py
@@ -66,7 +66,7 @@ class KankunSwitch(SwitchDevice):
         self._hass = hass
         self._name = name
         self._state = False
-        self._url = "http://{}:{}{}".format(host, port, path)
+        self._url = f"http://{host}:{port}{path}"
         if user is not None:
             self._auth = (user, passwd)
         else:
@@ -78,7 +78,7 @@ class KankunSwitch(SwitchDevice):
 
         try:
             req = requests.get(
-                "{}?set={}".format(self._url, newstate), auth=self._auth, timeout=5
+                f"{self._url}?set={newstate}", auth=self._auth, timeout=5
             )
             return req.json()["ok"]
         except requests.RequestException:
@@ -89,9 +89,7 @@ class KankunSwitch(SwitchDevice):
         _LOGGER.info("Querying state from: %s", self._url)
 
         try:
-            req = requests.get(
-                "{}?get=state".format(self._url), auth=self._auth, timeout=5
-            )
+            req = requests.get(f"{self._url}?get=state", auth=self._auth, timeout=5)
             return req.json()["state"] == "on"
         except requests.RequestException:
             _LOGGER.error("State query failed")
diff --git a/homeassistant/components/kira/__init__.py b/homeassistant/components/kira/__init__.py
index 24eb8b06aef..77f91a50dfa 100644
--- a/homeassistant/components/kira/__init__.py
+++ b/homeassistant/components/kira/__init__.py
@@ -32,7 +32,7 @@ CONF_REMOTES = "remotes"
 CONF_SENSOR = "sensor"
 CONF_REMOTE = "remote"
 
-CODES_YAML = "{}_codes.yaml".format(DOMAIN)
+CODES_YAML = f"{DOMAIN}_codes.yaml"
 
 CODE_SCHEMA = vol.Schema(
     {
diff --git a/homeassistant/components/kodi/media_player.py b/homeassistant/components/kodi/media_player.py
index 14ef0292ecc..9f0aab6c00c 100644
--- a/homeassistant/components/kodi/media_player.py
+++ b/homeassistant/components/kodi/media_player.py
@@ -140,7 +140,7 @@ def _check_deprecated_turn_off(hass, turn_off_action):
         method = DEPRECATED_TURN_OFF_ACTIONS[turn_off_action]
         new_config = OrderedDict(
             [
-                ("service", "{}.{}".format(DOMAIN, SERVICE_CALL_METHOD)),
+                ("service", f"{DOMAIN}.{SERVICE_CALL_METHOD}"),
                 (
                     "data_template",
                     OrderedDict([("entity_id", "{{ entity_id }}"), ("method", method)]),
@@ -281,18 +281,18 @@ class KodiDevice(MediaPlayerDevice):
 
         if username is not None:
             kwargs["auth"] = aiohttp.BasicAuth(username, password)
-            image_auth_string = "{}:{}@".format(username, password)
+            image_auth_string = f"{username}:{password}@"
         else:
             image_auth_string = ""
 
         http_protocol = "https" if encryption else "http"
         ws_protocol = "wss" if encryption else "ws"
 
-        self._http_url = "{}://{}:{}/jsonrpc".format(http_protocol, host, port)
+        self._http_url = f"{http_protocol}://{host}:{port}/jsonrpc"
         self._image_url = "{}://{}{}:{}/image".format(
             http_protocol, image_auth_string, host, port
         )
-        self._ws_url = "{}://{}:{}/jsonrpc".format(ws_protocol, host, tcp_port)
+        self._ws_url = f"{ws_protocol}://{host}:{tcp_port}/jsonrpc"
 
         self._http_server = jsonrpc_async.Server(self._http_url, **kwargs)
         if websocket:
@@ -326,14 +326,14 @@ class KodiDevice(MediaPlayerDevice):
             turn_on_action = script.Script(
                 self.hass,
                 turn_on_action,
-                "{} turn ON script".format(self.name),
+                f"{self.name} turn ON script",
                 self.async_update_ha_state(True),
             )
         if turn_off_action is not None:
             turn_off_action = script.Script(
                 self.hass,
                 _check_deprecated_turn_off(hass, turn_off_action),
-                "{} turn OFF script".format(self.name),
+                f"{self.name} turn OFF script",
             )
         self._turn_on_action = turn_on_action
         self._turn_off_action = turn_off_action
diff --git a/homeassistant/components/kodi/notify.py b/homeassistant/components/kodi/notify.py
index 70c8669019c..41dfc42b5de 100644
--- a/homeassistant/components/kodi/notify.py
+++ b/homeassistant/components/kodi/notify.py
@@ -62,7 +62,7 @@ async def async_get_service(hass, config, discovery_info=None):
         )
 
     http_protocol = "https" if encryption else "http"
-    url = "{}://{}:{}/jsonrpc".format(http_protocol, host, port)
+    url = f"{http_protocol}://{host}:{port}/jsonrpc"
 
     if username is not None:
         auth = aiohttp.BasicAuth(username, password)
diff --git a/homeassistant/components/konnected/__init__.py b/homeassistant/components/konnected/__init__.py
index d98f44bd3d9..4cc872fb78b 100644
--- a/homeassistant/components/konnected/__init__.py
+++ b/homeassistant/components/konnected/__init__.py
@@ -538,7 +538,7 @@ class KonnectedView(HomeAssistantView):
             )
 
         auth = request.headers.get(AUTHORIZATION, None)
-        if not hmac.compare_digest("Bearer {}".format(self.auth_token), auth):
+        if not hmac.compare_digest(f"Bearer {self.auth_token}", auth):
             return self.json_message("unauthorized", status_code=HTTP_UNAUTHORIZED)
         pin_num = int(pin_num)
         device = data[CONF_DEVICES].get(device_id)
diff --git a/homeassistant/components/kwb/sensor.py b/homeassistant/components/kwb/sensor.py
index 911884d2a9e..49815faf7ae 100644
--- a/homeassistant/components/kwb/sensor.py
+++ b/homeassistant/components/kwb/sensor.py
@@ -92,7 +92,7 @@ class KWBSensor(Entity):
     @property
     def name(self):
         """Return the name."""
-        return "{} {}".format(self._client_name, self._name)
+        return f"{self._client_name} {self._name}"
 
     @property
     def available(self) -> bool:
diff --git a/homeassistant/components/lastfm/sensor.py b/homeassistant/components/lastfm/sensor.py
index ce92cffee53..736792aefd8 100644
--- a/homeassistant/components/lastfm/sensor.py
+++ b/homeassistant/components/lastfm/sensor.py
@@ -72,7 +72,7 @@ class LastfmSensor(Entity):
     @property
     def entity_id(self):
         """Return the entity ID."""
-        return "sensor.lastfm_{}".format(self._name)
+        return f"sensor.lastfm_{self._name}"
 
     @property
     def state(self):
@@ -84,7 +84,7 @@ class LastfmSensor(Entity):
         self._cover = self._user.get_image()
         self._playcount = self._user.get_playcount()
         last = self._user.get_recent_tracks(limit=2)[0]
-        self._lastplayed = "{} - {}".format(last.track.artist, last.track.title)
+        self._lastplayed = f"{last.track.artist} - {last.track.title}"
         top = self._user.get_top_tracks(limit=1)[0]
         toptitle = re.search("', '(.+?)',", str(top))
         topartist = re.search("'(.+?)',", str(top))
@@ -93,7 +93,7 @@ class LastfmSensor(Entity):
             self._state = "Not Scrobbling"
             return
         now = self._user.get_now_playing()
-        self._state = "{} - {}".format(now.artist, now.title)
+        self._state = f"{now.artist} - {now.title}"
 
     @property
     def device_state_attributes(self):
diff --git a/homeassistant/components/lcn/helpers.py b/homeassistant/components/lcn/helpers.py
index 92d51512726..236035b0400 100644
--- a/homeassistant/components/lcn/helpers.py
+++ b/homeassistant/components/lcn/helpers.py
@@ -38,7 +38,7 @@ def has_unique_connection_names(connections):
             if suffix == 0:
                 connection[CONF_NAME] = DEFAULT_NAME
             else:
-                connection[CONF_NAME] = "{}{:d}".format(DEFAULT_NAME, suffix)
+                connection[CONF_NAME] = f"{DEFAULT_NAME}{suffix:d}"
 
     schema = vol.Schema(vol.Unique())
     schema([connection.get(CONF_NAME) for connection in connections])
diff --git a/homeassistant/components/life360/config_flow.py b/homeassistant/components/life360/config_flow.py
index be84d276422..6af999a575d 100644
--- a/homeassistant/components/life360/config_flow.py
+++ b/homeassistant/components/life360/config_flow.py
@@ -99,7 +99,7 @@ class Life360ConfigFlow(config_entries.ConfigFlow):
             )
             return self.async_abort(reason="unexpected")
         return self.async_create_entry(
-            title="{} (from configuration)".format(username),
+            title=f"{username} (from configuration)",
             data={
                 CONF_USERNAME: username,
                 CONF_PASSWORD: password,
diff --git a/homeassistant/components/life360/device_tracker.py b/homeassistant/components/life360/device_tracker.py
index dc5645a5216..ddd562ebfac 100644
--- a/homeassistant/components/life360/device_tracker.py
+++ b/homeassistant/components/life360/device_tracker.py
@@ -159,7 +159,7 @@ class Life360Scanner:
         _errs = self._errs.get(key, 0)
         if _errs < self._max_errs:
             self._errs[key] = _errs = _errs + 1
-            msg = "{}: {}".format(key, err_msg)
+            msg = f"{key}: {err_msg}"
             if _errs >= self._error_threshold:
                 if _errs == self._max_errs:
                     msg = "Suppressing further errors until OK: " + msg
@@ -233,14 +233,12 @@ class Life360Scanner:
                 convert(float(gps_accuracy), LENGTH_FEET, LENGTH_METERS)
             )
         except (TypeError, ValueError):
-            self._err(
-                dev_id, "GPS data invalid: {}, {}, {}".format(lat, lon, gps_accuracy)
-            )
+            self._err(dev_id, f"GPS data invalid: {lat}, {lon}, {gps_accuracy}")
             return
 
         self._ok(dev_id)
 
-        msg = "Updating {}".format(dev_id)
+        msg = f"Updating {dev_id}"
         if prev_seen:
             msg += "; Time since last update: {}".format(last_seen - prev_seen)
         _LOGGER.debug(msg)
@@ -401,7 +399,7 @@ class Life360Scanner:
                     except (Life360Error, KeyError):
                         pass
                 if incl_circle:
-                    err_key = 'get_circle_members "{}"'.format(circle_name)
+                    err_key = f'get_circle_members "{circle_name}"'
                     try:
                         members = api.get_circle_members(circle_id)
                     except Life360Error as exc:
diff --git a/homeassistant/components/lifx/light.py b/homeassistant/components/lifx/light.py
index b3ec9ed288f..ed26db3d49e 100644
--- a/homeassistant/components/lifx/light.py
+++ b/homeassistant/components/lifx/light.py
@@ -509,7 +509,7 @@ class LIFXLight(Light):
     @property
     def who(self):
         """Return a string identifying the bulb."""
-        return "%s (%s)" % (self.bulb.ip_addr, self.name)
+        return f"{self.bulb.ip_addr} ({self.name})"
 
     @property
     def min_mireds(self):
diff --git a/homeassistant/components/lifx_cloud/scene.py b/homeassistant/components/lifx_cloud/scene.py
index 6fc9fac1267..ac4e0201fb8 100644
--- a/homeassistant/components/lifx_cloud/scene.py
+++ b/homeassistant/components/lifx_cloud/scene.py
@@ -31,7 +31,7 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
     token = config.get(CONF_TOKEN)
     timeout = config.get(CONF_TIMEOUT)
 
-    headers = {AUTHORIZATION: "Bearer {}".format(token)}
+    headers = {AUTHORIZATION: f"Bearer {token}"}
 
     url = LIFX_API_URL.format("scenes")
 
diff --git a/homeassistant/components/light/__init__.py b/homeassistant/components/light/__init__.py
index 94ba43b8545..ed61d961d88 100644
--- a/homeassistant/components/light/__init__.py
+++ b/homeassistant/components/light/__init__.py
@@ -237,16 +237,16 @@ class SetIntentHandler(intent.IntentHandler):
         response = intent_obj.create_response()
 
         if not speech_parts:  # No attributes changed
-            speech = "Turned on {}".format(state.name)
+            speech = f"Turned on {state.name}"
         else:
-            parts = ["Changed {} to".format(state.name)]
+            parts = [f"Changed {state.name} to"]
             for index, part in enumerate(speech_parts):
                 if index == 0:
-                    parts.append(" {}".format(part))
+                    parts.append(f" {part}")
                 elif index != len(speech_parts) - 1:
-                    parts.append(", {}".format(part))
+                    parts.append(f", {part}")
                 else:
-                    parts.append(" and {}".format(part))
+                    parts.append(f" and {part}")
             speech = "".join(parts)
 
         response.async_set_speech(speech)
diff --git a/homeassistant/components/linksys_smart/device_tracker.py b/homeassistant/components/linksys_smart/device_tracker.py
index 9877f6ed091..1af84a4c4ab 100644
--- a/homeassistant/components/linksys_smart/device_tracker.py
+++ b/homeassistant/components/linksys_smart/device_tracker.py
@@ -100,7 +100,7 @@ class LinksysSmartWifiDeviceScanner(DeviceScanner):
         ]
         headers = {"X-JNAP-Action": "http://linksys.com/jnap/core/Transaction"}
         return requests.post(
-            "http://{}/JNAP/".format(self.host),
+            f"http://{self.host}/JNAP/",
             timeout=DEFAULT_TIMEOUT,
             headers=headers,
             json=data,
diff --git a/homeassistant/components/linux_battery/sensor.py b/homeassistant/components/linux_battery/sensor.py
index 9eb7090e957..9256c3ad18d 100644
--- a/homeassistant/components/linux_battery/sensor.py
+++ b/homeassistant/components/linux_battery/sensor.py
@@ -59,7 +59,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
         if system == "android":
             os.listdir(os.path.join(DEFAULT_PATH, "battery"))
         else:
-            os.listdir(os.path.join(DEFAULT_PATH, "BAT{}".format(battery_id)))
+            os.listdir(os.path.join(DEFAULT_PATH, f"BAT{battery_id}"))
     except FileNotFoundError:
         _LOGGER.error("No battery found")
         return False
diff --git a/homeassistant/components/liveboxplaytv/media_player.py b/homeassistant/components/liveboxplaytv/media_player.py
index 3c3c8bb9b38..98418d6be81 100644
--- a/homeassistant/components/liveboxplaytv/media_player.py
+++ b/homeassistant/components/liveboxplaytv/media_player.py
@@ -178,7 +178,7 @@ class LiveboxPlayTvDevice(MediaPlayerDevice):
         """Title of current playing media."""
         if self._current_channel:
             if self._current_program:
-                return "{}: {}".format(self._current_channel, self._current_program)
+                return f"{self._current_channel}: {self._current_program}"
             return self._current_channel
 
     @property
diff --git a/homeassistant/components/locative/__init__.py b/homeassistant/components/locative/__init__.py
index e1df5b980a9..61e0b1f7474 100644
--- a/homeassistant/components/locative/__init__.py
+++ b/homeassistant/components/locative/__init__.py
@@ -22,7 +22,7 @@ from homeassistant.helpers.dispatcher import async_dispatcher_send
 _LOGGER = logging.getLogger(__name__)
 
 DOMAIN = "locative"
-TRACKER_UPDATE = "{}_tracker_update".format(DOMAIN)
+TRACKER_UPDATE = f"{DOMAIN}_tracker_update"
 
 
 ATTR_DEVICE_ID = "device"
@@ -76,12 +76,10 @@ async def handle_webhook(hass, webhook_id, request):
 
     if direction == "enter":
         async_dispatcher_send(hass, TRACKER_UPDATE, device, gps_location, location_name)
-        return web.Response(
-            text="Setting location to {}".format(location_name), status=HTTP_OK
-        )
+        return web.Response(text=f"Setting location to {location_name}", status=HTTP_OK)
 
     if direction == "exit":
-        current_state = hass.states.get("{}.{}".format(DEVICE_TRACKER, device))
+        current_state = hass.states.get(f"{DEVICE_TRACKER}.{device}")
 
         if current_state is None or current_state.state == location_name:
             location_name = STATE_NOT_HOME
@@ -108,7 +106,7 @@ async def handle_webhook(hass, webhook_id, request):
 
     _LOGGER.error("Received unidentified message from Locative: %s", direction)
     return web.Response(
-        text="Received unidentified message: {}".format(direction),
+        text=f"Received unidentified message: {direction}",
         status=HTTP_UNPROCESSABLE_ENTITY,
     )
 
diff --git a/homeassistant/components/logbook/__init__.py b/homeassistant/components/logbook/__init__.py
index 0383e73105b..3c5e828765c 100644
--- a/homeassistant/components/logbook/__init__.py
+++ b/homeassistant/components/logbook/__init__.py
@@ -188,7 +188,7 @@ def humanify(hass, events):
     - if 2+ sensor updates in GROUP_BY_MINUTES, show last
     - if home assistant stop and start happen in same minute call it restarted
     """
-    domain_prefixes = tuple("{}.".format(dom) for dom in CONTINUOUS_DOMAINS)
+    domain_prefixes = tuple(f"{dom}." for dom in CONTINUOUS_DOMAINS)
 
     # Group events in batches of GROUP_BY_MINUTES
     for _, g_events in groupby(
@@ -332,7 +332,7 @@ def humanify(hass, events):
                 entity_id = data.get(ATTR_ENTITY_ID)
                 value = data.get(ATTR_VALUE)
 
-                value_msg = " to {}".format(value) if value else ""
+                value_msg = f" to {value}" if value else ""
                 message = "send command {}{} for {}".format(
                     data[ATTR_SERVICE], value_msg, data[ATTR_DISPLAY_NAME]
                 )
@@ -519,7 +519,7 @@ def _keep_event(event, entities_filter):
         domain = DOMAIN_HOMEKIT
 
     if not entity_id and domain:
-        entity_id = "%s." % (domain,)
+        entity_id = f"{domain}."
 
     return not entity_id or entities_filter(entity_id)
 
@@ -530,7 +530,7 @@ def _entry_message_from_state(domain, state):
     if domain in ["device_tracker", "person"]:
         if state.state == STATE_NOT_HOME:
             return "is away"
-        return "is at {}".format(state.state)
+        return f"is at {state.state}"
 
     if domain == "sun":
         if state.state == sun.STATE_ABOVE_HORIZON:
@@ -596,9 +596,9 @@ def _entry_message_from_state(domain, state):
             "vibration",
         ]:
             if state.state == STATE_ON:
-                return "detected {}".format(device_class)
+                return f"detected {device_class}"
             if state.state == STATE_OFF:
-                return "cleared (no {} detected)".format(device_class)
+                return f"cleared (no {device_class} detected)"
 
     if state.state == STATE_ON:
         # Future: combine groups and its entity entries ?
@@ -607,4 +607,4 @@ def _entry_message_from_state(domain, state):
     if state.state == STATE_OFF:
         return "turned off"
 
-    return "changed to {}".format(state.state)
+    return f"changed to {state.state}"
diff --git a/homeassistant/components/logentries/__init__.py b/homeassistant/components/logentries/__init__.py
index ba92fb8a672..3601ee275b8 100644
--- a/homeassistant/components/logentries/__init__.py
+++ b/homeassistant/components/logentries/__init__.py
@@ -24,7 +24,7 @@ def setup(hass, config):
     """Set up the Logentries component."""
     conf = config[DOMAIN]
     token = conf.get(CONF_TOKEN)
-    le_wh = "{}{}".format(DEFAULT_HOST, token)
+    le_wh = f"{DEFAULT_HOST}{token}"
 
     def logentries_event_listener(event):
         """Listen for new messages on the bus and sends them to Logentries."""
diff --git a/homeassistant/components/logi_circle/__init__.py b/homeassistant/components/logi_circle/__init__.py
index 6f073a064f1..12484a655d6 100644
--- a/homeassistant/components/logi_circle/__init__.py
+++ b/homeassistant/components/logi_circle/__init__.py
@@ -156,7 +156,7 @@ async def async_setup_entry(hass, entry):
     except asyncio.TimeoutError:
         # The TimeoutError exception object returns nothing when casted to a
         # string, so we'll handle it separately.
-        err = "{}s timeout exceeded when connecting to Logi Circle API".format(_TIMEOUT)
+        err = f"{_TIMEOUT}s timeout exceeded when connecting to Logi Circle API"
         hass.components.persistent_notification.create(
             "Error: {}<br />"
             "You will need to restart hass after fixing."
diff --git a/homeassistant/components/logi_circle/config_flow.py b/homeassistant/components/logi_circle/config_flow.py
index f81db9ba171..2a25c5f00a4 100644
--- a/homeassistant/components/logi_circle/config_flow.py
+++ b/homeassistant/components/logi_circle/config_flow.py
@@ -179,7 +179,7 @@ class LogiCircleFlowHandler(config_entries.ConfigFlow):
         account_id = (await logi_session.account)["accountId"]
         await logi_session.close()
         return self.async_create_entry(
-            title="Logi Circle ({})".format(account_id),
+            title=f"Logi Circle ({account_id})",
             data={
                 CONF_CLIENT_ID: client_id,
                 CONF_CLIENT_SECRET: client_secret,
diff --git a/homeassistant/components/logi_circle/sensor.py b/homeassistant/components/logi_circle/sensor.py
index f229250ea09..fc5ad7155b4 100644
--- a/homeassistant/components/logi_circle/sensor.py
+++ b/homeassistant/components/logi_circle/sensor.py
@@ -49,7 +49,7 @@ class LogiSensor(Entity):
         """Initialize a sensor for Logi Circle camera."""
         self._sensor_type = sensor_type
         self._camera = camera
-        self._id = "{}-{}".format(self._camera.mac_address, self._sensor_type)
+        self._id = f"{self._camera.mac_address}-{self._sensor_type}"
         self._icon = "mdi:{}".format(SENSOR_TYPES.get(self._sensor_type)[2])
         self._name = "{0} {1}".format(
             self._camera.name, SENSOR_TYPES.get(self._sensor_type)[0]
diff --git a/homeassistant/components/luftdaten/__init__.py b/homeassistant/components/luftdaten/__init__.py
index e05967a91fd..86129eafc02 100644
--- a/homeassistant/components/luftdaten/__init__.py
+++ b/homeassistant/components/luftdaten/__init__.py
@@ -34,7 +34,7 @@ SENSOR_PM2_5 = "P2"
 SENSOR_PRESSURE = "pressure"
 SENSOR_TEMPERATURE = "temperature"
 
-TOPIC_UPDATE = "{0}_data_update".format(DOMAIN)
+TOPIC_UPDATE = f"{DOMAIN}_data_update"
 
 VOLUME_MICROGRAMS_PER_CUBIC_METER = "µg/m3"
 
diff --git a/homeassistant/components/lutron/__init__.py b/homeassistant/components/lutron/__init__.py
index 9f4d81df044..de3ca40fd1d 100644
--- a/homeassistant/components/lutron/__init__.py
+++ b/homeassistant/components/lutron/__init__.py
@@ -114,7 +114,7 @@ class LutronDevice(Entity):
     @property
     def name(self):
         """Return the name of the device."""
-        return "{} {}".format(self._area_name, self._lutron_device.name)
+        return f"{self._area_name} {self._lutron_device.name}"
 
     @property
     def should_poll(self):
@@ -132,7 +132,7 @@ class LutronButton:
 
     def __init__(self, hass, keypad, button):
         """Register callback for activity on the button."""
-        name = "{}: {}".format(keypad.name, button.name)
+        name = f"{keypad.name}: {button.name}"
         self._hass = hass
         self._has_release_event = (
             button.button_type is not None and "RaiseLower" in button.button_type
diff --git a/homeassistant/components/lyft/sensor.py b/homeassistant/components/lyft/sensor.py
index 0bf739b040c..339b996c5d8 100644
--- a/homeassistant/components/lyft/sensor.py
+++ b/homeassistant/components/lyft/sensor.py
@@ -85,7 +85,7 @@ class LyftSensor(Entity):
         self._sensortype = sensorType
         self._name = "{} {}".format(self._product["display_name"], self._sensortype)
         if "lyft" not in self._name.lower():
-            self._name = "Lyft{}".format(self._name)
+            self._name = f"Lyft{self._name}"
         if self._sensortype == "time":
             self._unit_of_measurement = "min"
         elif self._sensortype == "price":
diff --git a/homeassistant/components/magicseaweed/sensor.py b/homeassistant/components/magicseaweed/sensor.py
index 61abb9788c5..66ab87a6569 100644
--- a/homeassistant/components/magicseaweed/sensor.py
+++ b/homeassistant/components/magicseaweed/sensor.py
@@ -108,10 +108,10 @@ class MagicSeaweedSensor(Entity):
     def name(self):
         """Return the name of the sensor."""
         if self.hour is None and "forecast" in self.type:
-            return "{} {}".format(self.client_name, self._name)
+            return f"{self.client_name} {self._name}"
         if self.hour is None:
-            return "Current {} {}".format(self.client_name, self._name)
-        return "{} {} {}".format(self.hour, self.client_name, self._name)
+            return f"Current {self.client_name} {self._name}"
+        return f"{self.hour} {self.client_name} {self._name}"
 
     @property
     def state(self):
diff --git a/homeassistant/components/mailgun/__init__.py b/homeassistant/components/mailgun/__init__.py
index 87bbe6bee07..4bcca0848f4 100644
--- a/homeassistant/components/mailgun/__init__.py
+++ b/homeassistant/components/mailgun/__init__.py
@@ -19,7 +19,7 @@ CONF_SANDBOX = "sandbox"
 
 DEFAULT_SANDBOX = False
 
-MESSAGE_RECEIVED = "{}_message_received".format(DOMAIN)
+MESSAGE_RECEIVED = f"{DOMAIN}_message_received"
 
 CONFIG_SCHEMA = vol.Schema(
     {
@@ -75,7 +75,7 @@ async def verify_webhook(hass, token=None, timestamp=None, signature=None):
 
     hmac_digest = hmac.new(
         key=bytes(hass.data[DOMAIN][CONF_API_KEY], "utf-8"),
-        msg=bytes("{}{}".format(timestamp, token), "utf-8"),
+        msg=bytes(f"{timestamp}{token}", "utf-8"),
         digestmod=hashlib.sha256,
     ).hexdigest()
 
diff --git a/homeassistant/components/marytts/tts.py b/homeassistant/components/marytts/tts.py
index 9f64c088b4a..e5088c5b2df 100644
--- a/homeassistant/components/marytts/tts.py
+++ b/homeassistant/components/marytts/tts.py
@@ -74,7 +74,7 @@ class MaryTTSProvider(Provider):
 
         try:
             with async_timeout.timeout(10):
-                url = "http://{}:{}/process?".format(self._host, self._port)
+                url = f"http://{self._host}:{self._port}/process?"
 
                 audio = self._codec.upper()
                 if audio == "WAV":
diff --git a/homeassistant/components/metoffice/weather.py b/homeassistant/components/metoffice/weather.py
index e90d6fdc4c2..bb7a64005ce 100644
--- a/homeassistant/components/metoffice/weather.py
+++ b/homeassistant/components/metoffice/weather.py
@@ -83,7 +83,7 @@ class MetOfficeWeather(WeatherEntity):
     @property
     def name(self):
         """Return the name of the sensor."""
-        return "{} {}".format(self._name, self.site.name)
+        return f"{self._name} {self.site.name}"
 
     @property
     def condition(self):
diff --git a/homeassistant/components/microsoft/tts.py b/homeassistant/components/microsoft/tts.py
index ff06e8815ed..3536c788bb9 100644
--- a/homeassistant/components/microsoft/tts.py
+++ b/homeassistant/components/microsoft/tts.py
@@ -115,8 +115,8 @@ class MicrosoftProvider(Provider):
         self._gender = gender
         self._type = ttype
         self._output = DEFAULT_OUTPUT
-        self._rate = "{}%".format(rate)
-        self._volume = "{}%".format(volume)
+        self._rate = f"{rate}%"
+        self._volume = f"{volume}%"
         self._pitch = pitch
         self._contour = contour
         self.name = "Microsoft"
diff --git a/homeassistant/components/microsoft_face/__init__.py b/homeassistant/components/microsoft_face/__init__.py
index 6c2fc5ae6bf..5d0c50e536a 100644
--- a/homeassistant/components/microsoft_face/__init__.py
+++ b/homeassistant/components/microsoft_face/__init__.py
@@ -92,7 +92,7 @@ async def async_setup(hass, config):
         g_id = slugify(name)
 
         try:
-            await face.call_api("put", "persongroups/{0}".format(g_id), {"name": name})
+            await face.call_api("put", f"persongroups/{g_id}", {"name": name})
             face.store[g_id] = {}
 
             entities[g_id] = MicrosoftFaceGroupEntity(hass, face, g_id, name)
@@ -109,7 +109,7 @@ async def async_setup(hass, config):
         g_id = slugify(service.data[ATTR_NAME])
 
         try:
-            await face.call_api("delete", "persongroups/{0}".format(g_id))
+            await face.call_api("delete", f"persongroups/{g_id}")
             face.store.pop(g_id)
 
             entity = entities.pop(g_id)
@@ -126,7 +126,7 @@ async def async_setup(hass, config):
         g_id = service.data[ATTR_GROUP]
 
         try:
-            await face.call_api("post", "persongroups/{0}/train".format(g_id))
+            await face.call_api("post", f"persongroups/{g_id}/train")
         except HomeAssistantError as err:
             _LOGGER.error("Can't train group '%s' with error: %s", g_id, err)
 
@@ -141,7 +141,7 @@ async def async_setup(hass, config):
 
         try:
             user_data = await face.call_api(
-                "post", "persongroups/{0}/persons".format(g_id), {"name": name}
+                "post", f"persongroups/{g_id}/persons", {"name": name}
             )
 
             face.store[g_id][name] = user_data["personId"]
@@ -160,9 +160,7 @@ async def async_setup(hass, config):
         p_id = face.store[g_id].get(name)
 
         try:
-            await face.call_api(
-                "delete", "persongroups/{0}/persons/{1}".format(g_id, p_id)
-            )
+            await face.call_api("delete", f"persongroups/{g_id}/persons/{p_id}")
 
             face.store[g_id].pop(name)
             await entities[g_id].async_update_ha_state()
@@ -186,7 +184,7 @@ async def async_setup(hass, config):
 
             await face.call_api(
                 "post",
-                "persongroups/{0}/persons/{1}/persistedFaces".format(g_id, p_id),
+                f"persongroups/{g_id}/persons/{p_id}/persistedFaces",
                 image.content,
                 binary=True,
             )
@@ -218,7 +216,7 @@ class MicrosoftFaceGroupEntity(Entity):
     @property
     def entity_id(self):
         """Return entity id."""
-        return "{0}.{1}".format(DOMAIN, self._id)
+        return f"{DOMAIN}.{self._id}"
 
     @property
     def state(self):
@@ -249,7 +247,7 @@ class MicrosoftFace:
         self.websession = async_get_clientsession(hass)
         self.timeout = timeout
         self._api_key = api_key
-        self._server_url = "https://{0}.{1}".format(server_loc, FACE_API_URL)
+        self._server_url = f"https://{server_loc}.{FACE_API_URL}"
         self._store = {}
         self._entities = entities
 
@@ -270,9 +268,7 @@ class MicrosoftFace:
                 self.hass, self, g_id, group["name"]
             )
 
-            persons = await self.call_api(
-                "get", "persongroups/{0}/persons".format(g_id)
-            )
+            persons = await self.call_api("get", f"persongroups/{g_id}/persons")
 
             for person in persons:
                 self._store[g_id][person["name"]] = person["personId"]
diff --git a/homeassistant/components/microsoft_face_detect/image_processing.py b/homeassistant/components/microsoft_face_detect/image_processing.py
index 243b4533938..c10f7edf9db 100644
--- a/homeassistant/components/microsoft_face_detect/image_processing.py
+++ b/homeassistant/components/microsoft_face_detect/image_processing.py
@@ -30,7 +30,7 @@ def validate_attributes(list_attributes):
     """Validate face attributes."""
     for attr in list_attributes:
         if attr not in SUPPORTED_ATTRIBUTES:
-            raise vol.Invalid("Invalid attribute {0}".format(attr))
+            raise vol.Invalid(f"Invalid attribute {attr}")
     return list_attributes
 
 
diff --git a/homeassistant/components/miflora/sensor.py b/homeassistant/components/miflora/sensor.py
index 999dc473c60..86f1462e2cc 100644
--- a/homeassistant/components/miflora/sensor.py
+++ b/homeassistant/components/miflora/sensor.py
@@ -85,7 +85,7 @@ async def async_setup_platform(hass, config, async_add_entities, discovery_info=
 
         prefix = config.get(CONF_NAME)
         if prefix:
-            name = "{} {}".format(prefix, name)
+            name = f"{prefix} {name}"
 
         devs.append(
             MiFloraSensor(poller, parameter, name, unit, icon, force_update, median)
diff --git a/homeassistant/components/minio/__init__.py b/homeassistant/components/minio/__init__.py
index cede3a7aad5..d411d913082 100644
--- a/homeassistant/components/minio/__init__.py
+++ b/homeassistant/components/minio/__init__.py
@@ -166,7 +166,7 @@ def setup(hass, config):
 
 def get_minio_endpoint(host: str, port: int) -> str:
     """Create minio endpoint from host and port."""
-    return "{}:{}".format(host, port)
+    return f"{host}:{port}"
 
 
 class QueueListener(threading.Thread):
diff --git a/homeassistant/components/mitemp_bt/sensor.py b/homeassistant/components/mitemp_bt/sensor.py
index c9b7837c683..9cd1f1cebc2 100644
--- a/homeassistant/components/mitemp_bt/sensor.py
+++ b/homeassistant/components/mitemp_bt/sensor.py
@@ -94,7 +94,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
 
         prefix = config.get(CONF_NAME)
         if prefix:
-            name = "{} {}".format(prefix, name)
+            name = f"{prefix} {name}"
 
         devs.append(
             MiTempBtSensor(poller, parameter, device, name, unit, force_update, median)
diff --git a/homeassistant/components/mobile_app/binary_sensor.py b/homeassistant/components/mobile_app/binary_sensor.py
index c0ea297edc1..975c4c16c32 100644
--- a/homeassistant/components/mobile_app/binary_sensor.py
+++ b/homeassistant/components/mobile_app/binary_sensor.py
@@ -53,7 +53,7 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
 
     async_dispatcher_connect(
         hass,
-        "{}_{}_register".format(DOMAIN, ENTITY_TYPE),
+        f"{DOMAIN}_{ENTITY_TYPE}_register",
         partial(handle_sensor_registration, webhook_id),
     )
 
diff --git a/homeassistant/components/mobile_app/entity.py b/homeassistant/components/mobile_app/entity.py
index c207475dc3c..27cb9934b18 100644
--- a/homeassistant/components/mobile_app/entity.py
+++ b/homeassistant/components/mobile_app/entity.py
@@ -21,7 +21,7 @@ from .helpers import device_info
 
 def sensor_id(webhook_id, unique_id):
     """Return a unique sensor ID."""
-    return "{}_{}".format(webhook_id, unique_id)
+    return f"{webhook_id}_{unique_id}"
 
 
 class MobileAppEntity(Entity):
diff --git a/homeassistant/components/mobile_app/sensor.py b/homeassistant/components/mobile_app/sensor.py
index d6d2247736c..b96a6f1e2f0 100644
--- a/homeassistant/components/mobile_app/sensor.py
+++ b/homeassistant/components/mobile_app/sensor.py
@@ -53,7 +53,7 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
 
     async_dispatcher_connect(
         hass,
-        "{}_{}_register".format(DOMAIN, ENTITY_TYPE),
+        f"{DOMAIN}_{ENTITY_TYPE}_register",
         partial(handle_sensor_registration, webhook_id),
     )
 
diff --git a/homeassistant/components/mobile_app/webhook.py b/homeassistant/components/mobile_app/webhook.py
index ecbd08375e0..f95d5b993f0 100644
--- a/homeassistant/components/mobile_app/webhook.py
+++ b/homeassistant/components/mobile_app/webhook.py
@@ -220,13 +220,13 @@ async def handle_webhook(
 
         unique_id = data[ATTR_SENSOR_UNIQUE_ID]
 
-        unique_store_key = "{}_{}".format(webhook_id, unique_id)
+        unique_store_key = f"{webhook_id}_{unique_id}"
 
         if unique_store_key in hass.data[DOMAIN][entity_type]:
             _LOGGER.error("Refusing to re-register existing sensor %s!", unique_id)
             return error_response(
                 ERR_SENSOR_DUPLICATE_UNIQUE_ID,
-                "{} {} already exists!".format(entity_type, unique_id),
+                f"{entity_type} {unique_id} already exists!",
                 status=409,
             )
 
@@ -257,13 +257,13 @@ async def handle_webhook(
 
             unique_id = sensor[ATTR_SENSOR_UNIQUE_ID]
 
-            unique_store_key = "{}_{}".format(webhook_id, unique_id)
+            unique_store_key = f"{webhook_id}_{unique_id}"
 
             if unique_store_key not in hass.data[DOMAIN][entity_type]:
                 _LOGGER.error(
                     "Refusing to update non-registered sensor: %s", unique_store_key
                 )
-                err_msg = "{} {} is not registered".format(entity_type, unique_id)
+                err_msg = f"{entity_type} {unique_id} is not registered"
                 resp[unique_id] = {
                     "success": False,
                     "error": {"code": ERR_SENSOR_NOT_REGISTERED, "message": err_msg},
diff --git a/homeassistant/components/mochad/light.py b/homeassistant/components/mochad/light.py
index a7b0b8c2d0f..899908c34bd 100644
--- a/homeassistant/components/mochad/light.py
+++ b/homeassistant/components/mochad/light.py
@@ -50,7 +50,7 @@ class MochadLight(Light):
 
         self._controller = ctrl
         self._address = dev[CONF_ADDRESS]
-        self._name = dev.get(CONF_NAME, "x10_light_dev_{}".format(self._address))
+        self._name = dev.get(CONF_NAME, f"x10_light_dev_{self._address}")
         self._comm_type = dev.get(mochad.CONF_COMM_TYPE, "pl")
         self.light = device.Device(ctrl, self._address, comm_type=self._comm_type)
         self._brightness = 0
@@ -95,12 +95,12 @@ class MochadLight(Light):
         if self._brightness > brightness:
             bdelta = self._brightness - brightness
             mochad_brightness = self._calculate_brightness_value(bdelta)
-            self.light.send_cmd("dim {}".format(mochad_brightness))
+            self.light.send_cmd(f"dim {mochad_brightness}")
             self._controller.read_data()
         elif self._brightness < brightness:
             bdelta = brightness - self._brightness
             mochad_brightness = self._calculate_brightness_value(bdelta)
-            self.light.send_cmd("bright {}".format(mochad_brightness))
+            self.light.send_cmd(f"bright {mochad_brightness}")
             self._controller.read_data()
 
     def turn_on(self, **kwargs):
@@ -109,7 +109,7 @@ class MochadLight(Light):
         with mochad.REQ_LOCK:
             if self._brightness_levels > 32:
                 out_brightness = self._calculate_brightness_value(brightness)
-                self.light.send_cmd("xdim {}".format(out_brightness))
+                self.light.send_cmd(f"xdim {out_brightness}")
                 self._controller.read_data()
             else:
                 self.light.send_cmd("on")
diff --git a/homeassistant/components/modbus/climate.py b/homeassistant/components/modbus/climate.py
index 22b871cea20..64b45b03c95 100644
--- a/homeassistant/components/modbus/climate.py
+++ b/homeassistant/components/modbus/climate.py
@@ -170,7 +170,7 @@ class ModbusThermostat(ClimateDevice):
             [x.to_bytes(2, byteorder="big") for x in result.registers]
         )
         val = struct.unpack(self._structure, byte_string)[0]
-        register_value = format(val, ".{}f".format(self._precision))
+        register_value = format(val, f".{self._precision}f")
         return register_value
 
     def write_register(self, register, value):
diff --git a/homeassistant/components/modbus/sensor.py b/homeassistant/components/modbus/sensor.py
index 4fc9fb808c6..1a5c71812d6 100644
--- a/homeassistant/components/modbus/sensor.py
+++ b/homeassistant/components/modbus/sensor.py
@@ -54,7 +54,7 @@ def number(value: Any) -> Union[int, float]:
         value = float(value)
         return value
     except (TypeError, ValueError):
-        raise vol.Invalid("invalid number {}".format(value))
+        raise vol.Invalid(f"invalid number {value}")
 
 
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend(
diff --git a/homeassistant/components/mopar/__init__.py b/homeassistant/components/mopar/__init__.py
index 686b927b515..857dbab2a3b 100644
--- a/homeassistant/components/mopar/__init__.py
+++ b/homeassistant/components/mopar/__init__.py
@@ -19,7 +19,7 @@ from homeassistant.helpers.dispatcher import dispatcher_send
 from homeassistant.helpers.event import track_time_interval
 
 DOMAIN = "mopar"
-DATA_UPDATED = "{}_data_updated".format(DOMAIN)
+DATA_UPDATED = f"{DOMAIN}_data_updated"
 
 _LOGGER = logging.getLogger(__name__)
 
diff --git a/homeassistant/components/mpchc/media_player.py b/homeassistant/components/mpchc/media_player.py
index d616ec6d1e8..ae96704be58 100644
--- a/homeassistant/components/mpchc/media_player.py
+++ b/homeassistant/components/mpchc/media_player.py
@@ -56,7 +56,7 @@ def setup_platform(hass, config, add_entities, discovery_info=None):
     host = config.get(CONF_HOST)
     port = config.get(CONF_PORT)
 
-    url = "{}:{}".format(host, port)
+    url = f"{host}:{port}"
 
     add_entities([MpcHcDevice(name, url)], True)
 
@@ -73,9 +73,7 @@ class MpcHcDevice(MediaPlayerDevice):
     def update(self):
         """Get the latest details."""
         try:
-            response = requests.get(
-                "{}/variables.html".format(self._url), data=None, timeout=3
-            )
+            response = requests.get(f"{self._url}/variables.html", data=None, timeout=3)
 
             mpchc_variables = re.findall(r'<p id="(.+?)">(.+?)</p>', response.text)
 
@@ -88,7 +86,7 @@ class MpcHcDevice(MediaPlayerDevice):
         """Send a command to MPC-HC via its window message ID."""
         try:
             params = {"wm_command": command_id}
-            requests.get("{}/command.html".format(self._url), params=params, timeout=3)
+            requests.get(f"{self._url}/command.html", params=params, timeout=3)
         except requests.exceptions.RequestException:
             _LOGGER.error(
                 "Could not send command %d to MPC-HC at: %s", command_id, self._url
diff --git a/homeassistant/components/mpd/media_player.py b/homeassistant/components/mpd/media_player.py
index 0d924cdd1d2..c19f8f49226 100644
--- a/homeassistant/components/mpd/media_player.py
+++ b/homeassistant/components/mpd/media_player.py
@@ -211,7 +211,7 @@ class MpdDevice(MediaPlayerDevice):
         if title is None:
             return name
 
-        return "{}: {}".format(name, title)
+        return f"{name}: {title}"
 
     @property
     def media_artist(self):
diff --git a/homeassistant/components/mqtt/discovery.py b/homeassistant/components/mqtt/discovery.py
index d611b8db13e..f393c315793 100644
--- a/homeassistant/components/mqtt/discovery.py
+++ b/homeassistant/components/mqtt/discovery.py
@@ -86,7 +86,7 @@ async def async_start(
         """Process the received message."""
         payload = msg.payload
         topic = msg.topic
-        topic_trimmed = topic.replace("{}/".format(discovery_topic), "", 1)
+        topic_trimmed = topic.replace(f"{discovery_topic}/", "", 1)
         match = TOPIC_MATCHER.match(topic_trimmed)
 
         if not match:
@@ -134,9 +134,7 @@ async def async_start(
 
         if payload:
             # Attach MQTT topic to the payload, used for debug prints
-            setattr(
-                payload, "__configuration_source__", "MQTT (topic: '{}')".format(topic)
-            )
+            setattr(payload, "__configuration_source__", f"MQTT (topic: '{topic}')")
 
             if CONF_PLATFORM in payload and "schema" not in payload:
                 platform = payload[CONF_PLATFORM]
diff --git a/homeassistant/components/mqtt/vacuum/schema_legacy.py b/homeassistant/components/mqtt/vacuum/schema_legacy.py
index 20be0dcf89c..f2fa8f8da66 100644
--- a/homeassistant/components/mqtt/vacuum/schema_legacy.py
+++ b/homeassistant/components/mqtt/vacuum/schema_legacy.py
@@ -339,7 +339,7 @@ class MqttVacuum(
             elif self._cleaning:
                 self._status = "Cleaning"
             elif self._error:
-                self._status = "Error: {}".format(self._error)
+                self._status = f"Error: {self._error}"
             else:
                 self._status = "Stopped"
 
@@ -360,7 +360,7 @@ class MqttVacuum(
             self.hass,
             self._sub_state,
             {
-                "topic{}".format(i): {
+                f"topic{i}": {
                     "topic": topic,
                     "msg_callback": message_received,
                     "qos": self._qos,
@@ -550,7 +550,7 @@ class MqttVacuum(
         mqtt.async_publish(
             self.hass, self._set_fan_speed_topic, fan_speed, self._qos, self._retain
         )
-        self._status = "Setting fan to {}...".format(fan_speed)
+        self._status = f"Setting fan to {fan_speed}..."
         self.async_write_ha_state()
 
     async def async_send_command(self, command, params=None, **kwargs):
@@ -566,5 +566,5 @@ class MqttVacuum(
         mqtt.async_publish(
             self.hass, self._send_command_topic, message, self._qos, self._retain
         )
-        self._status = "Sending command {}...".format(message)
+        self._status = f"Sending command {message}..."
         self.async_write_ha_state()
diff --git a/homeassistant/components/mysensors/__init__.py b/homeassistant/components/mysensors/__init__.py
index 2bde87976bc..cbedd947843 100644
--- a/homeassistant/components/mysensors/__init__.py
+++ b/homeassistant/components/mysensors/__init__.py
@@ -56,7 +56,7 @@ def is_persistence_file(value):
     """Validate that persistence file path ends in either .pickle or .json."""
     if value.endswith((".json", ".pickle")):
         return value
-    raise vol.Invalid("{} does not end in either `.json` or `.pickle`".format(value))
+    raise vol.Invalid(f"{value} does not end in either `.json` or `.pickle`")
 
 
 def deprecated(key):
@@ -138,7 +138,7 @@ def _get_mysensors_name(gateway, node_id, child_id):
         ),
         node_name,
     )
-    return "{} {}".format(node_name, child_id)
+    return f"{node_name} {child_id}"
 
 
 @callback
diff --git a/homeassistant/components/mysensors/gateway.py b/homeassistant/components/mysensors/gateway.py
index 28d49303835..366692205a7 100644
--- a/homeassistant/components/mysensors/gateway.py
+++ b/homeassistant/components/mysensors/gateway.py
@@ -44,7 +44,7 @@ def is_serial_port(value):
         ports = ("COM{}".format(idx + 1) for idx in range(256))
         if value in ports:
             return value
-        raise vol.Invalid("{} is not a serial port".format(value))
+        raise vol.Invalid(f"{value} is not a serial port")
     return cv.isdevice(value)
 
 
diff --git a/homeassistant/components/mysensors/notify.py b/homeassistant/components/mysensors/notify.py
index ac94a8559a1..99e731762df 100644
--- a/homeassistant/components/mysensors/notify.py
+++ b/homeassistant/components/mysensors/notify.py
@@ -26,7 +26,7 @@ class MySensorsNotificationDevice(mysensors.device.MySensorsDevice):
 
     def __repr__(self):
         """Return the representation."""
-        return "<MySensorsNotificationDevice {}>".format(self.name)
+        return f"<MySensorsNotificationDevice {self.name}>"
 
 
 class MySensorsNotificationService(BaseNotificationService):
diff --git a/homeassistant/components/mystrom/binary_sensor.py b/homeassistant/components/mystrom/binary_sensor.py
index 20d32be199e..ff0063a380e 100644
--- a/homeassistant/components/mystrom/binary_sensor.py
+++ b/homeassistant/components/mystrom/binary_sensor.py
@@ -41,19 +41,16 @@ class MyStromView(HomeAssistantView):
 
         if button_action is None:
             _LOGGER.error("Received unidentified message from myStrom button: %s", data)
-            return (
-                "Received unidentified message: {}".format(data),
-                HTTP_UNPROCESSABLE_ENTITY,
-            )
+            return (f"Received unidentified message: {data}", HTTP_UNPROCESSABLE_ENTITY)
 
         button_id = data[button_action]
-        entity_id = "{}.{}_{}".format(DOMAIN, button_id, button_action)
+        entity_id = f"{DOMAIN}.{button_id}_{button_action}"
         if entity_id not in self.buttons:
             _LOGGER.info(
                 "New myStrom button/action detected: %s/%s", button_id, button_action
             )
             self.buttons[entity_id] = MyStromBinarySensor(
-                "{}_{}".format(button_id, button_action)
+                f"{button_id}_{button_action}"
             )
             self.add_entities([self.buttons[entity_id]])
         else: