Custom shortcode: Display user role

/**
 * Adding the following to your functions.php file will give you a custom
 * shortcode to display a user's role.  The shortcode can be used as follows:
 *
 * [display_user_role] -> this would display the current user's role.
 *
 * [display_user_role id=123] -> displays the role for user ID 123.
 */
add_shortcode( 'display_user_role', function( $atts, $content, $tag ) {
    global $wp_roles;
    $user_id = ( isset( $atts['id'] ) ) ? $atts['id'] : get_current_user_id();
    $roles = wpmem_get_user_role( $user_id );
    if ( is_array( $roles ) ) {
        foreach ( $roles as $role ) {
            $display[] = translate_user_role( $wp_roles->roles[ $role ]['name'] );
        }
        $content = implode( ", ", $display );
    } else {
        $content = translate_user_role( $wp_roles->roles[ $roles ]['name'] );
    }
    return $content;
}, 10, 3);