Three errors that shouldn't be errors

Hello! I reimported an asset that has scripts that I am calling from my own script. Now I have three errors that really don't look like errors. error CS0123: A method or delegate `BuyTurboManager.OnTransactionComplete(IOSStoreKitResponse)' parameters do not match delegate `System.Action(IOSStoreKitResult)' parameters error CS0019: Operator `+=' cannot be applied to operands of type `System.Action' and `method group' error CS0428: Cannot convert method group `OnTransactionComplete' to non-delegate type `System.Action'. Consider using parentheses to invoke the method For this line: IOSInAppPurchaseManager.instance.OnTransactionComplete += OnTransactionComplete;