Hello. I tried this library and couldn't achieve any result. I got errors when tried examples from Readme. I guess that API responsed JSON with error description, then parser failed to get expected data fields:
or got an emty JSON, like here:

In this case API returns this error:
Parameter form_id is not required for all requests, may be its better make it parameter of methods where its required? I viewed in the code what is it, its not clear))