def skip_redundant(iterable, skipset=None):
    "Redundant items are repeated items or items in the original skipset."
    if skipset is None: skipset = set()
    for item in iterable:
        if item not in skipset:
            skipset.add(item)
            yield item
Redundant items are repeated items or items in the original skipset.
recipes/Python/204197_SOLVING_THE_METACLASS_CONFLICT/recipe-204197.py