def test_wrappedProtocol(self):
        """
        The wrapper function _WrapIProtocol gives an IProcessProtocol
        implementation that wraps over an IProtocol.
        """
        d = self.ep.connect(self.factory)
        self.successResultOf(d)
        wpp = self.reactor.processProtocol
        self.assertIsInstance(wpp, endpoints._WrapIProtocol)

        The wrapper function _WrapIProtocol gives an IProcessProtocol
        implementation that wraps over an IProtocol.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/internet/test/test_endpoints.py