def test_suggestThreadPoolSize(self):
        """
        C{reactor.suggestThreadPoolSize()} sets the maximum size of the reactor
        threadpool.
        """
        reactor = self.buildReactor()
        reactor.suggestThreadPoolSize(17)
        pool = reactor.getThreadPool()
        self.assertEqual(pool.max, 17)

        C{reactor.suggestThreadPoolSize()} sets the maximum size of the reactor
        threadpool.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_threads.py