code: def with_proxies(proxy_map, get_key):
      
      def wrapper(cls):
          for label, ProxiedClass in six.iteritems(proxy_map):
              proxy = proxy_factory(cls, label, ProxiedClass, get_key)
              setattr(cls, label, proxy)
          return cls
      return wrapper
docs: Class decorator factory; adds proxy class variables to target class.
  
      :param dict proxy_map: Mapping between class variable labels and proxied
          classes
      :param function get_key: Extension-specific key function; may return e.g.
          the current Flask request