gh-135056: Put kwarg on its own line in mock assertion.

Author: aisipos

Lib/test/test_httpservers.py

@@ -1513,7 +1513,8 @@ def test_extra_response_headers_arg(self, _, mock_make_server):
             # ensure extra_response_headers are passed to it
             httpd.finish_request(mock.Mock(), '127.0.0.1')
             mock_handler_init.assert_called_once_with(
-                mock.ANY, mock.ANY, mock.ANY, directory=mock.ANY,
+                mock.ANY, mock.ANY, mock.ANY,
+                directory=mock.ANY,
                 extra_response_headers=[
                     ['Set-Cookie', 'k=v'], ['Set-Cookie', 'k2=v2']
                 ]