How to use the daphne.testing.TestApplication function in daphne

# Clear result storage
        TestApplication.delete_setup()
        TestApplication.delete_result()
        # Option Daphne features
        kwargs = {}
        # Optionally enable X-Forwarded-For support.
        if self.xff:
            kwargs["proxy_forwarded_address_header"] = "X-Forwarded-For"
            kwargs["proxy_forwarded_port_header"] = "X-Forwarded-Port"
            kwargs["proxy_forwarded_proto_header"] = "X-Forwarded-Proto"
        if self.http_timeout:
            kwargs["http_timeout"] = self.http_timeout
        # Start up process
        self.process = DaphneProcess(
            host=self.host,
            application=TestApplication,
            kwargs=kwargs,
            setup=self.process_setup,
            teardown=self.process_teardown,
        )
        self.process.start()
        # Wait for the port
        if self.process.ready.wait(self.startup_timeout):
            self.port = self.process.port.value
            return self
        else:
            if self.process.errors.empty():
                raise RuntimeError("Daphne did not start up, no error caught")
            else:
                error, traceback = self.process.errors.get(False)
                raise RuntimeError("Daphne did not start up:\n%s" % traceback)