How to remove nested comments?

Question

Laravel

Good day everyone.
When you delete a parent comment, you need to delete its children and child children. That is, the nesting level is unknown and a recursive function is needed to remove it. And here with this complete plug. If anyone has an example of this, please share.
About onDelete('cascade') in the course, I would like to know how to solve this issue using recursion.
Thank you.