Woocommerce Cart Conditional Subtotal

I am working with a php function that is meant to compare the woocommerce cart subtotal with a conditional cart subtotal, which excludes products from one category, and reports the difference between the two. This is the code that I currently have to accomplish that:

function new_was_match_condition_subtotal( $match, $operator, $value ) {

	if ( ! isset( WC()->cart ) ) return;

	$subtotal = 0;
	foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
		$product = $cart_item['data'];
		$quantity = $cart_item['quantity'];

		if ( !has_term('donations', 'product_cat', $product->id) ) { 
			$products_subtotal = $product->get_price() * $quantity;
			$subtotal = $subtotal + $products_subtotal;
		}
	}

	if ( '==' == $operator ) :
		$match = ( $subtotal == $value );
	elseif ( '!=' == $operator ) :
		$match = ( $subtotal != $value );
	elseif ( '>=' == $operator ) :
		$match = ( $subtotal >= $value );
	elseif ( '<=' == $operator ) :
		$match = ( $subtotal <= $value );
	endif;

	return $match;

}

Unfortunately, since the last update, this function is no longer working. I expect that the problem is in the line which excludes the “donations” category from the conditional subtotal:
if ( !has_term('donations', 'product_cat', $product->id) ) {
But nothing I have tried for fixing this line has worked at all. Can anyone help me?