old_contents: import logging
  
  from .current_playlist import CurrentPlaylistController
  from .library import LibraryController, BaseLibraryProvider
  from .playback import PlaybackController, BasePlaybackProvider
  from .stored_playlists import (StoredPlaylistsController,
      BaseStoredPlaylistsProvider)
  
  logger = logging.getLogger('mopidy.backends.base')
  
  class Backend(object):
      #: The current playlist controller. An instance of
      #: :class:`mopidy.backends.base.CurrentPlaylistController`.
      current_playlist = None
  
      #: The library controller. An instance of
      # :class:`mopidy.backends.base.LibraryController`.
      library = None
  
      #: The sound mixer. An instance of :class:`mopidy.mixers.BaseMixer`.
      mixer = None
  
      #: The playback controller. An instance of
      #: :class:`mopidy.backends.base.PlaybackController`.
      playback = None
  
      #: The stored playlists controller. An instance of
      #: :class:`mopidy.backends.base.StoredPlaylistsController`.
      stored_playlists = None
  
      #: List of URI prefixes this backend can handle.
      uri_handlers = []
  
new_contents: import logging
  
  from .current_playlist import CurrentPlaylistController
  from .library import LibraryController, BaseLibraryProvider
  from .playback import PlaybackController, BasePlaybackProvider
  from .stored_playlists import (StoredPlaylistsController,
      BaseStoredPlaylistsProvider)
  
  logger = logging.getLogger('mopidy.backends.base')
  
  class Backend(object):
      #: The current playlist controller. An instance of
      #: :class:`mopidy.backends.base.CurrentPlaylistController`.
      current_playlist = None
  
      #: The library controller. An instance of
      # :class:`mopidy.backends.base.LibraryController`.
      library = None
  
      #: The playback controller. An instance of
      #: :class:`mopidy.backends.base.PlaybackController`.
      playback = None
  
      #: The stored playlists controller. An instance of
      #: :class:`mopidy.backends.base.StoredPlaylistsController`.
      stored_playlists = None
  
      #: List of URI prefixes this backend can handle.
      uri_handlers = []
  
subject: Remove mixer from the Backend API as it is independent