PNP4Nagios und PHP 7.2

Please check the documentation for information about the following error.
sizeof(): Parameter must be an array or an object that implements Countable
file [line]:
application/models/data.php [979]:

[...]
    /*
    * 
    */
    public function getFirstPage(){
        $pages = $this->getPages();
// chrissie
        if(is_array($pages) && sizeof($pages) > 0 ){
// end chrissie
            return urldecode($pages[0]);
        }else{
            return FALSE;
        }
    }
[...]