Comment 0 for bug 143941

Judging from the error message, you have not defined an interface but a class (*type* object ... has no attribute '__iro__').

Compare this with:

>>> class ICurrencyManager(object):
... pass
...
>>> ICurrencyManager.__iro__
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
AttributeError: type object 'ICurrencyManager' has no attribute '__iro__'

So, it seems you inherited from 'object' instead of 'zope.interface.Interface' by mistake.