Response fails its own type validation #71
Description
We are working on converting our API over to use the new advanced-billing-sdk. We have run into an issue for the subscriptionsController.readSubscription and subscriptionGroupsController.addSubscriptionToGroup methods where the method response fails its own type validation.
As you can see in this image, it expects an optional string, the actual returned value is null and it thinks the return type is object. The response is actually 200 ok and not an error response, it just refuses to give up the data.
We suspect this issue probably affects more methods than just these two. With the readSubscription method, there seemed to be a correlation between the user being canceled and the validation failures (presumably because it causes some values to be null). The root issue seems like the type validation just isn't properly handling for values that can be null.
Please help to resolve this quickly. We would like to use this sdk, but we need to be able to rely on it to return information back to our API consistently.