async def test_no_warning_if_func_has_no_outputs(self):
        """
        Ensures that if a function has no outputs, no warning is raised.
        """
        with gr.Blocks() as demo:
            button = gr.Button()

            def no_return():
                pass

            button.click(
                no_return,
                inputs=None,
                outputs=None,
            )
        with warnings.catch_warnings():
            warnings.simplefilter("error")
            await demo.postprocess_data(demo.fns[0], predictions=None, state=None)  # type: ignore

        Ensures that if a function has no outputs, no warning is raised.
        
test/test_blocks.py