def decr(self, key, value, default=0, time=100):
        """
        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
        """
        return self._incr_decr('decr', key, value, default, time)