trackContentImpression from tag manager

Tag Manager
1

I’m trying to track content impressions for a popup manually from tag manager.

<script>
_paq.push(['trackContentImpression', '{{DL - cContentName}}', '{{DL - cContentPiece}}', '{{DL - cContentUrl}}']);
</script>

In console, I get a error message “Method trackContentImpression is not valid”.

What am I doing wrong?