public function userCanContent($name, $op, $title) {
    $op = strtr($op, ['edit' => 'update']);
    $node = $this->getCore()->loadNodeByName($title);
    $access = $this->getCore()->nodeAccess($op, $name, $node);
    if (!$access) {
      throw new \Exception("{$name} cannot {$op} '{$title}' but it is supposed to.");
    }
  }