Autogenerated BatchPayment model class missing "status_attribute_string" (StatusAttributeString)  #133

The deserialized BatchPayment class returned by the "create_batch_payment" method seems to strip out the status_attribute_string attribute that is present on other classes of objects that support "summarize_errors=False" at creation, like Invoice and BankTransaction.

I have verified that StatusAttributeString is present on raw calls to the API and so it should be present here.