AttributeError: 'Payment' object has no attribute 'allowed_methods'

[zxpectre]

When passing customized list of allowed payment methods instead of None, flask's Payment in decorator.py seems never to declare self.allowed_methods so later this happends:

  File "/usr/local/lib/python3.5/dist-packages/two1/bitserv/flask/decorator.py", line 131, in contains_payment
    for method in self.allowed_methods:
AttributeError: 'Payment' object has no attribute 'allowed_methods'

Is this a bug or I'm missing something?