function list_term_locations_shortcode() {
    $terms = get_terms([
        'taxonomy'   => 'regions_loca',
        'hide_empty' => false,
        'parent'     => 0, 
    ]);

    if (empty($terms) || is_wp_error($terms)) {
        return '<p>no data</p>';
    }

    ob_start(); 
    ?>
    <div class="dth-list-term">
        <ul>
            <?php foreach ($terms as $term) : ?>
                <li>
                    <a href="<?php echo get_term_link($term); ?>"><?php echo esc_html($term->name); ?></a>
                    <?php
                    $child_terms = get_terms([
                        'taxonomy'   => 'regions_loca',
                        'hide_empty' => false,
                        'parent'     => $term->term_id,
                    ]);

                    if (!empty($child_terms) && !is_wp_error($child_terms)) :
                    ?>
                        <ul>
                            <?php foreach ($child_terms as $child) : ?>
                                <li>
                                    <a href="<?php echo get_term_link($child); ?>"><?php echo esc_html($child->name); ?></a>
                                    <?php
                                    $sub_child_terms = get_terms([
                                        'taxonomy'   => 'regions_loca',
                                        'hide_empty' => false,
                                        'parent'     => $child->term_id,
                                    ]);

                                    if (!empty($sub_child_terms) && !is_wp_error($sub_child_terms)) :
                                    ?>
                                        <ul>
                                            <?php foreach ($sub_child_terms as $sub_child) : ?>
                                                <li><a href="<?php echo get_term_link($sub_child); ?>"><?php echo esc_html($sub_child->name); ?></a></li>
                                            <?php endforeach; ?>
                                        </ul>
                                    <?php endif; ?>
                                </li>
                            <?php endforeach; ?>
                        </ul>
                    <?php endif; ?>
                </li>
            <?php endforeach; ?>
        </ul>
    </div>
    <?php
    return ob_get_clean(); 
}

add_shortcode('list_term_locations', 'list_term_locations_shortcode');