core-bundle/src/Resources/contao/library/Contao/TemplateInheritance.php
public function insert($name, array $data=null)
	{
		/** @var Template $tpl */
		if ($this instanceof Template)
		{
			$tpl = new static($name);
		}
		elseif (TL_MODE == 'BE')
		{
			$tpl = new BackendTemplate($name);
		}
		else
		{
			$tpl = new FrontendTemplate($name);
		}

		if ($data !== null)
		{
			$tpl->setData($data);
		}

		echo $tpl->parse();
	}
public function insert($name, array $data=null)
	{
		/** @var Template $tpl */
		if ($this instanceof Template)
		{
			$tpl = new static($name);
		}
		elseif (TL_MODE == 'BE')
		{
			$tpl = new BackendTemplate($name);
		}
		else
		{
			$tpl = new FrontendTemplate($name);
		}

		if ($data !== null)
		{
			$tpl->setData($data);
		}

		echo $tpl->parse();
	}
Insert a template

@param string $name The template name
@param array  $data An optional data array