InitResponse has no error attribute when success=False

[pondem87]

Paynow-Python-SDK/paynow/model.py

Line 119 in ad0212e

if not self.success:

Here you return from constructor if not successful i.e. there was an error. However you return before assigning the error value to the error attribute which results in a run time exception when one tries to access the error attribute after the call was not successful. Fix this by "self.error = data["error"]" before return.