old_contents: import logging
  import multiprocessing
  
  from spotify import Link, SpotifyError
  
  from mopidy.backends.base import BaseLibraryController
  from mopidy.backends.libspotify import ENCODING
  from mopidy.backends.libspotify.translator import LibspotifyTranslator
  
  logger = logging.getLogger('mopidy.backends.libspotify.library')
  
  class LibspotifyLibraryController(BaseLibraryController):
      def find_exact(self, **query):
          return self.search(**query)
  
      def lookup(self, uri):
          try:
              spotify_track = Link.from_string(uri).as_track()
              # TODO Block until metadata_updated callback is called. Before that
              # the track will be unloaded, unless it's already in the stored
              # playlists.
              return LibspotifyTranslator.to_mopidy_track(spotify_track)
          except SpotifyError as e:
              logger.warning(u'Failed to lookup: %s', track.uri, e)
              return None
  
      def refresh(self, uri=None):
          pass # TODO
  
      def search(self, **query):
          spotify_query = []
          for (field, values) in query.iteritems():
              if not hasattr(values, '__iter__'):
                  values = [values]
              for value in values:
                  if field == u'track':
                      field = u'title'
                  if field == u'any':
                      spotify_query.append(value)
                  else:
                      spotify_query.append(u'%s:"%s"' % (field, value))
          spotify_query = u' '.join(spotify_query)
          logger.debug(u'Spotify search query: %s' % spotify_query)
          my_end, other_end = multiprocessing.Pipe()
          self.backend.spotify.search(spotify_query.encode(ENCODING), other_end)
          my_end.poll(None)
          playlist = my_end.recv()
          return playlist
  
new_contents: import logging
  import multiprocessing
  
  from spotify import Link, SpotifyError
  
  from mopidy.backends.base import BaseLibraryController
  from mopidy.backends.libspotify import ENCODING
  from mopidy.backends.libspotify.translator import LibspotifyTranslator
  
  logger = logging.getLogger('mopidy.backends.libspotify.library')
  
  class LibspotifyLibraryController(BaseLibraryController):
      def find_exact(self, **query):
          return self.search(**query)
  
      def lookup(self, uri):
          try:
              spotify_track = Link.from_string(uri).as_track()
              # TODO Block until metadata_updated callback is called. Before that
              # the track will be unloaded, unless it's already in the stored
              # playlists.
              return LibspotifyTranslator.to_mopidy_track(spotify_track)
          except SpotifyError as e:
              logger.warning(u'Failed to lookup: %s', uri, e)
              return None
  
      def refresh(self, uri=None):
          pass # TODO
  
      def search(self, **query):
          spotify_query = []
          for (field, values) in query.iteritems():
              if not hasattr(values, '__iter__'):
                  values = [values]
              for value in values:
                  if field == u'track':
                      field = u'title'
                  if field == u'any':
                      spotify_query.append(value)
                  else:
                      spotify_query.append(u'%s:"%s"' % (field, value))
          spotify_query = u' '.join(spotify_query)
          logger.debug(u'Spotify search query: %s' % spotify_query)
          my_end, other_end = multiprocessing.Pipe()
          self.backend.spotify.search(spotify_query.encode(ENCODING), other_end)
          my_end.poll(None)
          playlist = my_end.recv()
          return playlist
  
subject: Fix missing variable