fatal error due to bug

The current code in decimal-product-quantity-for-woocommerce.php is:

        add_filter (‘woocommerce_quantity_input_args’, ‘WooDecimalProduct_filter_quantity_input_args’, 999999, 2); function WooDecimalProduct_filter_quantity_input_args($args, $product) {

if (product) {

This is generating a fatal error in some circumstances due to a missing $ on line 47. It should be $product