list child pages

function lcas_list_children( $atts, $content ) {
        global $post;
        ob_start();
        $args = array(
                'post_parent' => $post->ID,
                'post_type' => 'page',
                'orderby' => 'title',
                'order' => 'ASC',
                );
        $myquery = new WP_Query( $args );
        if ( $myquery->have_posts() ) {
                while ( $myquery->have_posts() ) {
                        $myquery->the_post();
                        echo '<h2><a href="' . get_the_permalink() . '">';
                        the_title();
                        echo '</a></h2>';
                        the_excerpt();
                }
        } else {
                echo 'No pages found';
        }
        wp_reset_query();
        return '<div class="child_pages">' . ob_get_clean() . '</div>';
}
add_shortcode( 'list_child_pages', 'lcas_list_children' );