<?php


/**
     * Get  elements by parent ID.
     */
    public function getChildren($parent_id)
    {
        $elements = array();
        foreach ($this->elements as $k => $element) {
            if (isset($v['#parent']) && $v['#parent'] == $parent_id) {
                $elements[$k] = $element;
            }
        }

        return $elements;
    }


    /**
     * Remove an element by ID, Check it has children items. We also remove it.
     */

    public function removeElement($id)
    {

        $elements = $this->elements;
        if (isset($elements[$id])) {
            unset($elements[$id]);

            $this->elements = $elements;

            $children = $this->getChildren($id);

            if (!empty($children)) {
                foreach ($children as $k => $element) {
                    $this->removeElement($k); // Recursive!!!

                }
            }
        }

        $this->update(); // save builder to cache after updated
    }