public function render($request, Exception $exception)
{
    /**
     * in GrahamCampbell\Exceptions doesn't invoke method 'unauthenticated'
     * so we need to invoke this method by self
     */
    if (get_class($exception) == 'Illuminate\Auth\AuthenticationException') {
        return $this->unauthenticated($request, $exception);
    }
    return parent::render($request, $exception);
}