def test_keepaliveNotForwarded(self):
        """
        The proxy doesn't really know what to do with keepalive things from
        the remote server, so we stomp over any keepalive header we get from
        the client.
        """
        headers = {
            b"accept": b"text/html",
            b'keep-alive': b'300',
            b'connection': b'keep-alive',
            }
        expectedHeaders = headers.copy()
        expectedHeaders[b'connection'] = b'close'
        del expectedHeaders[b'keep-alive']
        client = ProxyClient(b'GET', b'/foo', b'HTTP/1.0', headers, b'', None)
        self.assertForwardsHeaders(
            client, b'GET /foo HTTP/1.0', expectedHeaders)

        The proxy doesn't really know what to do with keepalive things from
        the remote server, so we stomp over any keepalive header we get from
        the client.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/test/test_proxy.py