function multi2array($array) {
    static $result_array = array();
    foreach ($array as $key => $value) {
        if (is_array($value)) {
            multi2array($value);
        }
        else{
            $result_array[] = $value;
        }
    }
    return $result_array;
}

function _arr($array,$return=[]){
    array_walk_recursive($array,function($value)use(&$return){$return[]=$value;});
    return $return;
}