WPB WMCA NAV Walker

<?php

class WPB_WMCA_Nav_Walker extends Walker_Nav_Menu{

    function display_element( $element, &$children_elements, $max_depth, $depth=0, $args, &$output ){

        $id_field = $this->db_fields['id'];
        if ( is_object( $args[0] ) ) {
            $args[0]->has_children = ! empty( $children_elements[$element->$id_field] );
        }
        return parent::display_element( $element, $children_elements, $max_depth, $depth, $args, $output );
    }

    function start_el( &$output, $item, $depth, $args ) {

        if ( $args->has_children ){
            $attributes .= ' href="#"';
        }elseif( ! empty( $item->url ) ){
            $attributes .= ' href="'   . esc_attr( $item->url        ) .'"';
        }
    }
}