limited wallet

hi
add_filter(‘is_valid_payment_through_wallet’, ‘__return_false’);
add_filter(‘woo_wallet_partial_payment_amount’, ‘woo_wallet_partial_payment_amount_callback’);
function woo_wallet_partial_payment_amount_callback($amount){
return (woo_wallet()->wallet->get_wallet_balance( get_current_user_id(), ‘edit’ ) * 20) / 100;
}
The above code reduces the wallet by 20%, but I want to pay only 20% of the shopping cart with the wallet.