def write(data):
        """
        Write some data to the body of the response to this request.  Response
        headers are written the first time this method is called, after which
        new response headers may not be added.

        @param data: Bytes of the response body.
        @type data: L{bytes}
        """

        Write some data to the body of the response to this request.  Response
        headers are written the first time this method is called, after which
        new response headers may not be added.

        @param data: Bytes of the response body.
        @type data: L{bytes}
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/web/iweb.py