public function getClassBodyStyles(core_kernel_classes_Class $itemClass){
        $usages = [];
        $union = [];
        $intersect = [];
        $items = $itemClass->getInstances(true);
        $i = 0;
        foreach($items as $item){
            if($this->isQtiItem($item)){
                try{
                    $styles = $this->getBodyStyles($item);
                    $usages[$item->getUri()] = $styles;
                    if($i){
                        $intersect = array_intersect($styles, $intersect);
                    }else{
                        $intersect = $styles;
                    }
                    $union = array_unique(array_merge($styles, $union));
                    $i++;
                }catch(\common_Exception $e){}
            }
        }
        return [
            'all' => $union,
            'checked' => $intersect,
            'indeterminate' => array_values(array_diff($union, $intersect))
        ];
    }