def send_error(self, status_code=500, **kwargs):
        if self._headers_written:
            gen_log.error("Cannot send error response after headers written")
            if not self._finished:
                self.finish()
            return
        self.clear()

        reason = None
        if 'exc_info' in kwargs:
            exception = kwargs['exc_info'][1]
            if isinstance(exception, HTTPError) and exception.reason:
                reason = exception.reason
        self.set_status(status_code, reason=reason)
        try:
            self.write_error(status_code, **kwargs)
        except Exception:
            app_log.error("Uncaught exception in write_error", exc_info=True)
        if not self._finished:
            self.finish()
get value with uncertainties (uncertainties.ufloat)
dataset/ETHPy150Open RobotWebTools/rosbridge_suite/rosbridge_server/src/tornado/web.py/RequestHandler.send_error--crossover with--dataset/ETHPy150Open xraypy/xraylarch/lib/fitting/parameter.py/Parameter.uvalue