/** * Constructor. * * @param string $block Navigation block * @param string $key * @param string $title * * @throws InvalidArgumentException */ public function __construct($block, $key, $title) { if (!is_string($block)) { throw new InvalidArgumentException('Expecting $block to be a string, ' . gettype($block) . 'given!'); } $this->block = $block; parent::__construct($key, $title); }