/**
* 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);
}
