def system_drop_keyspace(self, keyspace):
    """
    drops a keyspace and any column families that are part of it. returns the new schema id.

    Parameters:
     - keyspace
    """
    self._seqid += 1
    d = self._reqs[self._seqid] = defer.Deferred()
    self.send_system_drop_keyspace(keyspace)
    return d