def METHOD_NAME(json_app: Sanic):
    custom_dumps = Mock(return_value="custom")
    @json_app.get("/json-custom")
    async def handle_custom(request: Request):
        return json_response(JSON_BODY, dumps=custom_dumps, prry="platypus")
    _, resp = json_app.test_client.get("/json-custom")
    assert resp.body == "custom".encode()
    custom_dumps.assert_called_once_with(JSON_BODY, prry="platypus")