Type ytmusic search filter as a Literal

ytmusicapi 1.12.1 narrows the `filter` argument of `search()` from
`str | None` to a `Literal[...]`, so passing our `str | None` value fails
mypy. Add a `YTMSearchFilter` Literal alias for the filter values we use
and apply it to the search helper and its caller.

The alias is a subset of ytmusicapi's accepted values and remains
assignable to the current 1.11.5 `str | None` signature, so the change is
backward-compatible and can land independently of the bump.

Author: OzGav

music_assistant/providers/ytmusic/__init__.py

@@ -63,6 +63,7 @@
 from music_assistant.models.music_provider import MusicProvider
 
 from .helpers import (
+    YTMSearchFilter,
     add_remove_playlist_tracks,
     convert_to_netscape,
     determine_recommendation_icon,
@@ -241,7 +242,7 @@ async def search(
         :param limit: Number of items to return in the search (per type).
         """
         parsed_results = SearchResults()
-        ytm_filter = None
+        ytm_filter: YTMSearchFilter | None = None
         if len(media_types) == 1:
             # YTM does not support multiple searchtypes, falls back to all if no type given
             if media_types[0] == MediaType.ARTIST:

music_assistant/providers/ytmusic/helpers.py

@@ -9,14 +9,17 @@
 import asyncio
 from http.cookies import SimpleCookie
 from time import time
-from typing import Any
+from typing import Any, Literal
 
 import ytmusicapi
 from ytmusicapi import LikeStatus
 from ytmusicapi.exceptions import YTMusicError
 
 from music_assistant.providers.ytmusic.constants import YTMRecommendationIcons
 
+# subset of ytmusicapi's accepted search filters that we use
+YTMSearchFilter = Literal["artists", "albums", "songs", "playlists"]
+
 
 async def get_artist(
     prov_artist_id: str, headers: dict[str, str], language: str = "en"
@@ -319,7 +322,7 @@ def _get_song_radio_tracks() -> dict[str, Any]:
 
 
 async def search(
-    query: str, ytm_filter: str | None = None, limit: int = 20, language: str = "en"
+    query: str, ytm_filter: YTMSearchFilter | None = None, limit: int = 20, language: str = "en"
 ) -> list[dict[str, Any]]:
     """Async wrapper around the ytmusicapi search function."""