':param location: database filename prefix (default: ``\'cache\'``)
:param fast_save: Speedup cache saving up to 50 times but with possibility of data loss.
See :ref:`backends.DbDict <backends_dbdict>` for more info
:param extension: extension for filename (default: ``\'.sqlite\'``)'

def __init__(self, location='cache', fast_save=False, extension='.sqlite', **options):

    super(DbCache, self).__init__()
    self.responses = DbPickleDict((location + extension), 'responses', fast_save=fast_save)
    self.url_map = DbDict((location + extension), 'urls')
