Define SwitchEntity entity attributes as class variables (#51232)

homeassistant/components/switch/__init__.py

@@ -1,22 +1,27 @@
 """Component to interface with switches that can be controlled remotely."""
+from __future__ import annotations
+
 from datetime import timedelta
 import logging
-from typing import final
+from typing import Any, cast, final
 
 import voluptuous as vol
 
+from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
     SERVICE_TOGGLE,
     SERVICE_TURN_OFF,
     SERVICE_TURN_ON,
     STATE_ON,
 )
+from homeassistant.core import HomeAssistant
 from homeassistant.helpers.config_validation import (  # noqa: F401
     PLATFORM_SCHEMA,
     PLATFORM_SCHEMA_BASE,
 )
 from homeassistant.helpers.entity import ToggleEntity
 from homeassistant.helpers.entity_component import EntityComponent
+from homeassistant.helpers.typing import ConfigType
 from homeassistant.loader import bind_hass
 
 # mypy: allow-untyped-defs, no-check-untyped-defs
@@ -55,7 +60,7 @@ def is_on(hass, entity_id):
     return hass.states.is_state(entity_id, STATE_ON)
 
 
-async def async_setup(hass, config):
+async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
     """Track states and offer events for switches."""
     component = hass.data[DOMAIN] = EntityComponent(
         _LOGGER, DOMAIN, hass, SCAN_INTERVAL
@@ -69,37 +74,41 @@ async def async_setup(hass, config):
     return True
 
 
-async def async_setup_entry(hass, entry):
+async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     """Set up a config entry."""
-    return await hass.data[DOMAIN].async_setup_entry(entry)
+    return cast(bool, await hass.data[DOMAIN].async_setup_entry(entry))
 
 
-async def async_unload_entry(hass, entry):
+async def async_unload_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     """Unload a config entry."""
-    return await hass.data[DOMAIN].async_unload_entry(entry)
+    return cast(bool, await hass.data[DOMAIN].async_unload_entry(entry))
 
 
 class SwitchEntity(ToggleEntity):
     """Base class for switch entities."""
 
+    _attr_current_power_w: float | None = None
+    _attr_is_standby: bool | None = None
+    _attr_today_energy_kwh: float | None = None
+
     @property
-    def current_power_w(self):
+    def current_power_w(self) -> float | None:
         """Return the current power usage in W."""
-        return None
+        return self._attr_current_power_w
 
     @property
-    def today_energy_kwh(self):
+    def today_energy_kwh(self) -> float | None:
         """Return the today total energy usage in kWh."""
-        return None
+        return self._attr_today_energy_kwh
 
     @property
-    def is_standby(self):
+    def is_standby(self) -> bool | None:
         """Return true if device is in standby."""
-        return None
+        return self._attr_is_standby
 
     @final
     @property
-    def state_attributes(self):
+    def state_attributes(self) -> dict[str, Any] | None:
         """Return the optional state attributes."""
         data = {}
 
@@ -110,11 +119,6 @@ class SwitchEntity(ToggleEntity):
 
         return data
 
-    @property
-    def device_class(self):
-        """Return the class of this device, from component DEVICE_CLASSES."""
-        return None
-
 
 class SwitchDevice(SwitchEntity):
     """Representation of a switch (for backwards compatibility)."""