docs: def list_slaves(self):
          '''Print information about the slave agencies.'''
          resp = []
          for slave_id, slave in self._broker.slaves.iteritems():
              resp += ["#### Slave %s ####" % slave_id]
              table = yield slave.callRemote('list_agents')
              resp += [table]
              resp += []
          defer.returnValue("\n".join(resp))