docs: 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