payment request error response when parsing response to json because of url_type is null

[gabriellafran22]

i am using github.com/xendit/xendit-go/v4 v4.1.0
this is what it says on the action because of the payment request action url type is required to be string. but what i received from the response is null

docs package:

response:

for the payment request i use ewallet shopeepay