public function output()
{
if (!isset($this->_template)) {
throw new Ergo\Exception("Not template file has been assigned");
}
$oldInclude = get_include_path();
set_include_path(implode(PATH_SEPARATOR, $this->_include));
$contents = $this->_renderTemplate($this->_template, $this->_vars);
set_include_path($oldInclude);
return $contents;
}