docs: def play_backend_uri(argv=None):
      '''Get album or track from backend uri and play all tracks found.
  
      uri is a string which represents some directory belonging to a backend.
  
      Calls LibraryController.browse(uri) to get an album and LibraryController.lookup(uri)
      to get track'''
  
      if argv is None:
          argv = sys.argv[1:]
      parser = argparse.ArgumentParser(description='Browse directories and tracks at the given uri and play them/it.')
      parser.add_argument('uri',
                          help='The key that represents some directory belonging to a backend. E.g. plex:album:2323 or spotify:album:xxxx')
      parser.add_argument('-l', '--loglevel', help='Logging level. Default: %(default)s.',
          choices=('debug', 'info', 'warning', 'error'), default='warning')
      args = parse_args_and_apply_logging_level(parser, argv)
      server = getServer()
      hits = server.core.library.browse(args.uri)
      # browse(): Returns a list of mopidy.models.Ref objects for the directories and tracks at the given uri.
      logging.info('Got hits from browse(): %r', hits)
      if len(hits) == 0:
          # try track lookup
          hits = server.core.library.lookup(args.uri)
          logging.info('Got hits from lookup() : %r', hits)
  
      if len(hits) == 0:
          print('No hits for "{}"'.format(args.uri))
      else:
          server.core.tracklist.clear()
          logging.debug('got special uris: %r', [t['uri'] for t in hits])
          server.core.tracklist.add(uris=[t['uri'] for t in hits])
          server.core.playback.play()