def METHOD_NAME(bar):
    with self.trace("b"):
        m = 4
        try:
            a(bar % m)
        except ValueError:
            # this would act differently for PY2 and PY3
            # PY3 would chain those KeyError to ValueError exc and we will have a single exc_id
            # PY2 would not chain those and have 2 exc_ids
            raise KeyError("chain it")