def set_etag_header(self):
        """Sets the response's Etag header using ``self.compute_etag()``.

        Note: no header will be set if ``compute_etag()`` returns ``None``.

        This method is called automatically when the request is finished.
        """
        etag = self.compute_etag()
        if etag is not None:
            self.set_header("Etag", etag)
dataset/ETHPy150Open RobotWebTools/rosbridge_suite/rosbridge_server/src/tornado/web.py/RequestHandler.set_etag_header/original