old_contents: import logging
  
  from spotify.manager import SpotifyContainerManager as \
      PyspotifyContainerManager
  
  logger = logging.getLogger('mopidy.backends.spotify.container_manager')
  
  class SpotifyContainerManager(PyspotifyContainerManager):
      def __init__(self, session_manager):
          PyspotifyContainerManager.__init__(self)
          self.session_manager = session_manager
  
      def container_loaded(self, container, userdata):
          """Callback used by pyspotify."""
          logger.debug(u'Container loaded')
          self.session_manager.refresh_stored_playlists()
  
new_contents: import logging
  
  from spotify.manager import SpotifyContainerManager as \
      PyspotifyContainerManager
  
  logger = logging.getLogger('mopidy.backends.spotify.container_manager')
  
  class SpotifyContainerManager(PyspotifyContainerManager):
      def __init__(self, session_manager):
          PyspotifyContainerManager.__init__(self)
          self.session_manager = session_manager
  
      def container_loaded(self, container, userdata):
          """Callback used by pyspotify"""
          logger.debug(u'Callback called: playlist container loaded')
          self.session_manager.refresh_stored_playlists()
  
      def playlist_added(self, container, playlist, position, userdata):
          """Callback used by pyspotify"""
          logger.debug(u'Callback called: playlist "%s" added at position %d',
              playlist.name(), position)
          # container_loaded() is called after this callback, so we do not need
          # to handle this callback.
  
      def playlist_moved(self, container, playlist, old_position, new_position,
              userdata):
          """Callback used by pyspotify"""
          logger.debug(
              u'Callback called: playlist "%s" moved from position %d to %d',
              playlist.name(), old_position, new_position)
          # container_loaded() is called after this callback, so we do not need
          # to handle this callback.
  
      def playlist_removed(self, container, playlist, position, userdata):
          """Callback used by pyspotify"""
          logger.debug(
              u'Callback called: playlist "%s" removed from position %d',
              playlist.name(), position)
          # container_loaded() is called after this callback, so we do not need
          # to handle this callback.
  
subject: Add missing container callbacks with debug log statements