Filter advanced search options in Omeka

Omeka - filter advanced search

    public $_filters = array('elements_select_options');
    
    public function filterElementsSelectOptions($elementSets)
    {
        //make this magic happen only on the advanced search page
        
        if(!is_admin_theme()) {
            $elementsWeWant = array('Title');
            
            foreach($elementSets as $elementSet=>$elements) {
                foreach($elements as $id=>$element) {
                    if(!in_array($element, $elementsWeWant)) {
                        unset($elementSets[$elementSet][$id]);                    
                    }
                }
            }
        }
        return $elementSets;
    }