'Builds up the path to a fanart cache for a given Indexer ID
:param indexer_id: ID of the show to use in the file name
:return: a full path to the cached fanart file for the given Indexer ID'

def fanart_path(self, indexer_id):

    fanart_file_name = (str(indexer_id) + u'.fanart.jpg')
    return os.path.join(self._cache_dir(), fanart_file_name)
