Add type annotations to config.py (#791)

mypy.ini

@@ -19,4 +19,4 @@ disallow_untyped_decorators = true
 disallow_untyped_defs = true
 warn_return_any = true
 warn_unreachable = true
-files = pychromecast/const.py, pychromecast/error.py, pychromecast/models.py, pychromecast/response_handler.py
+files = pychromecast/config.py, pychromecast/const.py, pychromecast/error.py, pychromecast/models.py, pychromecast/response_handler.py

pychromecast/config.py

@@ -2,6 +2,7 @@
 Data and methods to retrieve app specific configuration
 """
 import json
+from typing import cast
 
 import requests
 
@@ -22,7 +23,7 @@
 APP_NRKRADIO = "A49874B1"
 
 
-def get_possible_app_ids():
+def get_possible_app_ids() -> list[str]:
     """Returns all possible app ids."""
 
     try:
@@ -32,22 +33,25 @@ def get_possible_app_ids():
         )
         data = json.loads(req.text[4:])
 
-        return [app["app_id"] for app in data["applications"]] + data["enabled_app_ids"]
+        return cast(
+            list[str],
+            [app["app_id"] for app in data["applications"]] + data["enabled_app_ids"],
+        )
 
     except ValueError:
         # If json fails to parse
         return []
 
 
-def get_app_config(app_id):
+def get_app_config(app_id: str) -> dict:
     """Get specific configuration for 'app_id'."""
     try:
         req = requests.get(
             f"https://clients3.google.com/cast/chromecast/device/app?a={app_id}",
             timeout=10,
         )
 
-        return json.loads(req.text[4:]) if req.status_code == 200 else {}
+        return cast(dict, json.loads(req.text[4:])) if req.status_code == 200 else {}
 
     except ValueError:
         # If json fails to parse