Those attributes are class-level, so you don't need to instantiate the class to see them. All you need is a handle to the class. For example, the following program works:
Code:
class Foo(object):
dont = frozenset(['toolbar-device', 'context-menu-device'])
def bar(self):
pass
print Foo.dont
If the class Foo were in a separate file, then importing the class is sufficient.