code: def decr(self, key, value, default=0, time=100):
          
          return self._incr_decr('decr', key, value, default, time)
docs: Decrement a key, if it exists, returns its actual value, if it doesn't, return 0.
          Minimum value of decrement return is 0.
  
          :param key: Key's name
          :type key: six.string_types
          :param value: Number to be decremented
          :type value: int
          :param default: Default value if key does not exist.
          :type default: int
          :param time: Time in seconds to expire key.
          :type time: int
          :return: Actual value of the key on server
          :rtype: int