public function obj()
    {
        if ($this->obj === null) {
            $objId   = filter_input(INPUT_GET, 'obj_id', FILTER_SANITIZE_STRING);
            $objType = filter_input(INPUT_GET, 'obj_type', FILTER_SANITIZE_STRING);
            if ($objId && $objType) {
                $obj = $this->modelFactory()->create($objType);
                $obj->load($objId);

                $this->obj = $obj;
            } else {
                throw new InvalidArgumentException('Missing Object Type or ID');
            }
        }

        return $this->obj;
    }