I have dictionary that is built as part of the initialization of my object. I know that it will not change during the lifetime of the object. The dictionary maps keys to sets. I want to convert all the values from sets to frozensets, to make sure they do not get changed. Currently I do that like this:

for key in self.my_dict.iterkeys():
    self.my_dict[key] = frozenset(self.my_dict[key])

Is there a simpler way to achieve this? I cannot build frozenset right away, because I do not how much items will be in each set until i have built the complete dictionary.