python import bjoern def hello_world_app(environ, start_response): response_body = b"Hello, World!" status = "200 OK" response_headers = [("Content-Type", "text/plain"), ("Content-Length", str(len(response_body)))] start_response(status, response_headers) return [response_body] if __name__ == "__main__": host = "localhost" port = 8000 bjoern.run(hello_world_app, host, port)