private function _checkViewsExist()
    {
        foreach ( $this->_view_levels as $view_level )
        {
            if ( !$view_level["is_disabled"] )
            {
                if ( !file_exists($this->_views_dir . $view_level["file_name"] . ".phtml") )
                {
                    throw new \Exception( "View '". $view_level["file_name"] .".phtml' does not exist." );
                }
            }
        }
    }