cascade style sheets in a child theme

<?php
/* code to add to the functions.php of a child theme. This ensures the parent theme's css is loaded so you can override things in your child theme stylesheet. */

/* include default style and our override */
add_filter( 'wp_enqueue_scripts', 'iae2_scripts_styles' );
function iae2_scripts_styles() {
    /*
     * Loads our main stylesheets
     */
    wp_register_style( 'ias2-style', path_join( get_template_directory_uri(), 'style.css' ) );
    wp_enqueue_style( 'ias2-style' );

    wp_register_style( 'ias-nf2-style', path_join( get_stylesheet_directory_uri(), 'style.css' ) );
    wp_enqueue_style( 'ias-nf2-style' );
}