code: protected function handleException(\Throwable $e, Request $request) : Response
      {
          // Wrap non HTTP exception/errors
          if (!$e instanceof Exception\Exception) {
              $e = new Exception\UncaughtException($e);
          }
          
          // Throw to an appropriate handler
          $code = $e->getStatusCode();
          if ($this->exceptionHandlers[$code] instanceof ExceptionHandler) {
              return $this->exceptionHandlers[$code]->handle($e, $request);
          } elseif ($this->defaultExceptionHandler instanceof ExceptionHandler) {
              return $this->defaultExceptionHandler->handle($e, $request);
          } else {
              return (new \Circuit\ExceptionHandler\DefaultHandler)->handle($e, $request);
          }
      }
docs: Handle an exception during processing of route.
  
  @param Throwable $e The Exception / Error thrown.
  @param Request $request The request that caused the exception.
  @return Response The response to the exception (e.g. error page)