undup

[Skaperen]

Assuming that objective is to dedupe hashable objects in iterable while maintaining order:

def dedupe(iterable):
    seen = set()
    for item in iterable:
        if item not in seen:
            yield item
            seen.add(item)

either hashable or references to the same object. so a set() won't do; it will need to be a list, at least for the non-hashables. deep leaf comparison is not needed.

so, it doesn't pre-exist.