diff --git a/homeassistant/components/demo/lock.py b/homeassistant/components/demo/lock.py
index 63f2d218957..cafc0e3f748 100644
--- a/homeassistant/components/demo/lock.py
+++ b/homeassistant/components/demo/lock.py
@@ -22,44 +22,26 @@ async def async_setup_entry(hass, config_entry, async_add_entities):
 class DemoLock(LockEntity):
     """Representation of a Demo lock."""
 
-    def __init__(self, name, state, openable=False):
+    _attr_should_poll = False
+
+    def __init__(self, name: str, state: str, openable: bool = False) -> None:
         """Initialize the lock."""
-        self._name = name
-        self._state = state
-        self._openable = openable
-
-    @property
-    def should_poll(self):
-        """No polling needed for a demo lock."""
-        return False
-
-    @property
-    def name(self):
-        """Return the name of the lock if any."""
-        return self._name
-
-    @property
-    def is_locked(self):
-        """Return true if lock is locked."""
-        return self._state == STATE_LOCKED
+        self._attr_name = name
+        self._attr_is_locked = state == STATE_LOCKED
+        if openable:
+            self._attr_supported_features = SUPPORT_OPEN
 
     def lock(self, **kwargs):
         """Lock the device."""
-        self._state = STATE_LOCKED
+        self._attr_is_locked = True
         self.schedule_update_ha_state()
 
     def unlock(self, **kwargs):
         """Unlock the device."""
-        self._state = STATE_UNLOCKED
+        self._attr_is_locked = False
         self.schedule_update_ha_state()
 
     def open(self, **kwargs):
         """Open the door latch."""
-        self._state = STATE_UNLOCKED
+        self._attr_is_locked = False
         self.schedule_update_ha_state()
-
-    @property
-    def supported_features(self):
-        """Flag supported features."""
-        if self._openable:
-            return SUPPORT_OPEN
diff --git a/homeassistant/components/lock/__init__.py b/homeassistant/components/lock/__init__.py
index c74289b8794..1ca7404d56a 100644
--- a/homeassistant/components/lock/__init__.py
+++ b/homeassistant/components/lock/__init__.py
@@ -1,4 +1,6 @@
 """Component to interface with locks that can be controlled remotely."""
+from __future__ import annotations
+
 from datetime import timedelta
 import functools as ft
 import logging
@@ -83,20 +85,25 @@ async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
 class LockEntity(Entity):
     """Base class for lock entities."""
 
+    _attr_changed_by: str | None = None
+    _attr_code_format: str | None = None
+    _attr_is_locked: bool | None = None
+    _attr_state: None = None
+
     @property
-    def changed_by(self):
+    def changed_by(self) -> str | None:
         """Last change triggered by."""
-        return None
+        return self._attr_changed_by
 
     @property
-    def code_format(self):
+    def code_format(self) -> str | None:
         """Regex for code format or None if no code is required."""
-        return None
+        return self._attr_code_format
 
     @property
-    def is_locked(self):
+    def is_locked(self) -> bool | None:
         """Return true if the lock is locked."""
-        return None
+        return self._attr_is_locked
 
     def lock(self, **kwargs):
         """Lock the lock."""
@@ -133,8 +140,9 @@ class LockEntity(Entity):
                 state_attr[attr] = value
         return state_attr
 
+    @final
     @property
-    def state(self):
+    def state(self) -> str | None:
         """Return the state."""
         locked = self.is_locked
         if locked is None: