Adds @member to the set
            -> #int the number of @members that were added to the set,
                excluding pre-existing members (1 or 0)

def add(self, member):
        """ Adds @member to the set
            -> #int the number of @members that were added to the set,
                excluding pre-existing members (1 or 0)
        """
        return self._client.sadd(self.key_prefix, self._dumps(member))