text: #!/usr/bin/env python
  # -*- coding: utf-8 -*-
  """
      requests_cache.backends.sqlite
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  
      ``sqlite3`` cache backend
  """
  from .base import BaseCache
  from .storage.dbdict import DbDict, DbPickleDict
  
  
  class DbCache(BaseCache):
      """ sqlite cache backend.
  
      Reading is fast, saving is a bit slower. It can store big amount of data
      with low memory usage.
      """
      def __init__(self, location='cache',
                   fast_save=False, extension='.sqlite', **options):
          """
          :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'``)
          """
          super(DbCache, self).__init__(**options)
          self.responses = DbPickleDict(location + extension, 'responses', fast_save=fast_save)
          self.keys_map = DbDict(location + extension, 'urls')
  