docs: def system_add_keyspace(self, ks_def):
      """
      adds a keyspace and any column families that are part of it. returns the new schema id.
  
      Parameters:
       - ks_def
      """
      self._seqid += 1
      d = self._reqs[self._seqid] = defer.Deferred()
      self.send_system_add_keyspace(ks_def)
      return d