core-bundle/src/Resources/contao/elements/ContentTeaser.php
public function generate()
	{
		$objArticle = ArticleModel::findPublishedById($this->article);

		if ($objArticle === null)
		{
			return '';
		}

		// Use findPublished() instead of getRelated()
		$objParent = PageModel::findPublishedById($objArticle->pid);

		if ($objParent === null)
		{
			return '';
		}

		$this->objArticle = $objArticle;
		$this->objParent = $objParent;

		return parent::generate();
	}
public function generate()
	{
		$objArticle = ArticleModel::findPublishedById($this->article);

		if ($objArticle === null)
		{
			return '';
		}

		// Use findPublished() instead of getRelated()
		$objParent = PageModel::findPublishedById($objArticle->pid);

		if ($objParent === null)
		{
			return '';
		}

		$this->objArticle = $objArticle;
		$this->objParent = $objParent;

		return parent::generate();
	}
Check whether the target page and the article are published

@return string