private function extractFilterVars(array $filter)
    {
        $collection = array_key_exists('collection', $filter) ? $filter['collection'] : null;
        $systemCollections = array_key_exists('systemCollections', $filter) ? $filter['systemCollections'] : true;
        $types = array_key_exists('types', $filter) ? $filter['types'] : null;
        $search = array_key_exists('search', $filter) ? $filter['search'] : null;
        $orderBy = array_key_exists('orderBy', $filter) ? $filter['orderBy'] : null;
        $orderSort = array_key_exists('orderSort', $filter) ? $filter['orderSort'] : null;
        $ids = array_key_exists('ids', $filter) ? $filter['ids'] : null;

        return [$collection, $systemCollections, $types, $search, $orderBy, $orderSort, $ids];
    }