Improve `google_assistant` typing (#86537)

homeassistant/components/google_assistant/helpers.py

@@ -3,7 +3,7 @@ from __future__ import annotations
 
 from abc import ABC, abstractmethod
 from asyncio import gather
-from collections.abc import Mapping
+from collections.abc import Callable, Mapping
 from datetime import datetime, timedelta
 from http import HTTPStatus
 import logging
@@ -85,7 +85,7 @@ def _get_registry_entries(
 class AbstractConfig(ABC):
     """Hold the configuration for Google Assistant."""
 
-    _unsub_report_state = None
+    _unsub_report_state: Callable[[], None] | None = None
 
     def __init__(self, hass):
         """Initialize abstract config."""

homeassistant/components/google_assistant/trait.py

@@ -2,7 +2,7 @@
 from __future__ import annotations
 
 import logging
-from typing import Any
+from typing import Any, TypeVar
 
 from homeassistant.components import (
     alarm_control_panel,
@@ -161,13 +161,15 @@ COMMAND_SELECT_CHANNEL = f"{PREFIX_COMMANDS}selectChannel"
 COMMAND_LOCATE = f"{PREFIX_COMMANDS}Locate"
 COMMAND_CHARGE = f"{PREFIX_COMMANDS}Charge"
 
-TRAITS = []
+TRAITS: list[type[_Trait]] = []
 
 FAN_SPEED_MAX_SPEED_COUNT = 5
 
+_TraitT = TypeVar("_TraitT", bound="_Trait")
 
-def register_trait(trait):
-    """Decorate a function to register a trait."""
+
+def register_trait(trait: type[_TraitT]) -> type[_TraitT]:
+    """Decorate a class to register a trait."""
     TRAITS.append(trait)
     return trait
 
@@ -288,7 +290,7 @@ class CameraStreamTrait(_Trait):
     name = TRAIT_CAMERA_STREAM
     commands = [COMMAND_GET_CAMERA_STREAM]
 
-    stream_info = None
+    stream_info: dict[str, str] | None = None
 
     @staticmethod
     def supported(domain, features, device_class, _):