I came across a bug today that involved the re-definition of a dictionary that was being looped over within the loop. A simple example is something like: ``` my_dict = {"a": 1, "b": 2, "c": 3} some_other_dict = {"x": 99} for key in my_dict.keys(): print(my_dict[key]) my_dict = some_other_dict ``` Python continues to iterate over the original `my_dict`, but to the poor developer's surprise, Python spits out a KeyError on the second loop. Add in enough lines of code to disguise it (and, in my case, some bonus recursion of dictionaries-within-dictionaries), and this turns out to be quite an awkward error to diagnose. One doesn't receive a RuntimeError, as the original `my_dict` is not modified during iteration. It seems neither pylint or flake8 don't catch this. Is it possible to add a warning for this situation? There are somewhat similar checks already for imported variables that are redefined, or variables that are defined but then overwritten without ever being used/read. Regards, Daniel