Encapsulating the rules for whether the request was to a Flask endpoint

def _has_fr_route(self):
        """Encapsulating the rules for whether the request was to a Flask endpoint"""
        # 404's, 405's, which might not have a url_rule
        if self._should_use_fr_error_handler():
            return True
        # for all other errors, just check if FR dispatched the route
        if not request.url_rule:
            return False
        return self.owns_endpoint(request.url_rule.endpoint)