get grandchilds Sectuib titles

[josuevalrob]

Hello!. In the articleMainText.tpl there is a cicle that gets the child section tigles.

{foreach from=$sect->getChildSectionsTitles() item=secCont key=subsectionNumber}
      <a class="intranav nav-link ml-3 my-1" href="#sec-{$sectionNumber-1}-{$subsectionNumber}">{$secCont}</a>
{/foreach} 

Is there a way to create an inner section for this section to call the grandchild section titles?.

In my XML file they are:

And I want to print in the left summary of the article 3 levels.

The section.in.php file gives a clue

/* @var $type int type os a section: 1, 2, 3, 4 -> what means section, subsection, subsubsection, etc. */
	private $type;