Override implementation to report all exceptions to sentry, even
        after self.flush() or self.finish() is called, for pre-v3.1 Tornado.

def send_error(self, status_code=500, **kwargs):
        """Override implementation to report all exceptions to sentry, even
        after self.flush() or self.finish() is called, for pre-v3.1 Tornado.
        """
        if hasattr(super(SentryMixin, self), 'log_exception'):
            return super(SentryMixin, self).send_error(status_code, **kwargs)
        else:
            rv = super(SentryMixin, self).send_error(status_code, **kwargs)
            if 500 <= status_code <= 599:
                self.captureException(exc_info=kwargs.get('exc_info'))
            return rv