Weight of composite product

Hello,

I use a custom code for show the weight of products in cart. It’s good for me to calculate the EPR tax in Hungary, but my code isn’t work with composite product.

• The whole weight depends on the parts. I know the weight of every single composite, but I want show in summarize.
  Could you please help how find I the whole weight of composite product?

Thanks! Gabor

/** weight of product in chart **/
add_filter( 'woocommerce_get_item_data', 'displaying_cart_items_weight', 10, 2 );
function displaying_cart_items_weight( $item_data, $cart_item ) {
    $item_weight = $cart_item['data']->get_weight() * $cart_item['quantity'];
    $item_data[] = array(
        'key'       => __('Weight', 'woocommerce'),
        'value'     => $item_weight,
        'display'   => $item_weight . ' ' . get_option('woocommerce_weight_unit')
    );
    return $item_data;
}

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