filtering-element-wrap-classes.php

<?php

/**
 * Filters the element wrap classes.
 *
 * @param array   $wrap_classes Array of wrap classes.
 * @param Element $element      Element object.
 */
function add_element_wrapper_class( $wrapper_classes, $element ) {
	// If wanted, selecting a specific element
	if( 33 !== $element->id ) {
		return $wrapper_classes;
	}

	$wrapper_classes[] = 'my-css-class';
	return $wrapper_classes;
}

add_filter( 'torro_element_wrap_classes', 'add_element_wrapper_class', 10 , 2 );