def test_defaultPool(self):
        """
        If no pool is passed in, the L{Agent} creates a non-persistent pool.
        """
        agent = client.Agent(self.reactor)
        self.assertIsInstance(agent._pool, HTTPConnectionPool)
        self.assertEqual(agent._pool.persistent, False)
        self.assertIdentical(agent._reactor, agent._pool._reactor)

        If no pool is passed in, the L{Agent} creates a non-persistent pool.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_agent.py