How to solve it?
Warning line 52 file /.../override/classes/PaymentModule.php
[2] Declaration of PaymentModule::validateOrder($id_cart, $id_order_state, $amount_paid, $payment_method = 'Unknown', $message = NULL, $extra_vars = Array, $currency_special = NULL, $dont_touch_amount = false, $secure_key = false, ?Shop $shop = NULL) should be compatible with PaymentModuleCore::validateOrder($id_cart, $id_order_state, $amount_paid, $payment_method = 'Unknown', $message = NULL, $extra_vars = Array, $currency_special = NULL, $dont_touch_amount = false, $secure_key = false, ?Shop $shop = NULL, ?string $order_reference = NULL)
