Demo: Remote improvements (#52265)

* Demo: Remote improvements

* Address pylint warning

homeassistant/components/demo/remote.py

@@ -1,14 +1,32 @@
 """Demo platform that has two fake remotes."""
+from __future__ import annotations
+
+from collections.abc import Iterable
+from typing import Any
+
 from homeassistant.components.remote import RemoteEntity
+from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import DEVICE_DEFAULT_NAME
+from homeassistant.core import HomeAssistant
+from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.typing import ConfigType
 
 
-async def async_setup_entry(hass, config_entry, async_add_entities):
+async def async_setup_entry(
+    hass: HomeAssistant,
+    config_entry: ConfigEntry,
+    async_add_entities: AddEntitiesCallback,
+) -> None:
     """Set up the Demo config entry."""
     setup_platform(hass, {}, async_add_entities)
 
 
-def setup_platform(hass, config, add_entities_callback, discovery_info=None):
+def setup_platform(
+    hass: HomeAssistant,
+    config: ConfigType,
+    add_entities_callback: AddEntitiesCallback,
+    discovery_info: dict[str, Any] | None = None,
+) -> None:
     """Set up the demo remotes."""
     add_entities_callback(
         [
@@ -21,50 +39,32 @@ def setup_platform(hass, config, add_entities_callback, discovery_info=None):
 class DemoRemote(RemoteEntity):
     """Representation of a demo remote."""
 
-    def __init__(self, name, state, icon):
+    _attr_should_poll = False
+
+    def __init__(self, name: str | None, state: bool, icon: str | None) -> None:
         """Initialize the Demo Remote."""
-        self._name = name or DEVICE_DEFAULT_NAME
-        self._state = state
-        self._icon = icon
+        self._attr_name = name or DEVICE_DEFAULT_NAME
+        self._attr_is_on = state
+        self._attr_icon = icon
         self._last_command_sent = None
 
     @property
-    def should_poll(self):
-        """No polling needed for a demo remote."""
-        return False
-
-    @property
-    def name(self):
-        """Return the name of the device if any."""
-        return self._name
-
-    @property
-    def icon(self):
-        """Return the icon to use for device if any."""
-        return self._icon
-
-    @property
-    def is_on(self):
-        """Return true if remote is on."""
-        return self._state
-
-    @property
-    def extra_state_attributes(self):
+    def extra_state_attributes(self) -> dict[str, Any] | None:
         """Return device state attributes."""
         if self._last_command_sent is not None:
             return {"last_command_sent": self._last_command_sent}
 
-    def turn_on(self, **kwargs):
+    def turn_on(self, **kwargs: Any) -> None:
         """Turn the remote on."""
-        self._state = True
+        self._attr_is_on = True
         self.schedule_update_ha_state()
 
-    def turn_off(self, **kwargs):
+    def turn_off(self, **kwargs: Any) -> None:
         """Turn the remote off."""
-        self._state = False
+        self._attr_is_on = False
         self.schedule_update_ha_state()
 
-    def send_command(self, command, **kwargs):
+    def send_command(self, command: Iterable[str], **kwargs: Any) -> None:
         """Send a command to a device."""
         for com in command:
             self._last_command_sent = com