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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def union(a: Iterable[Any], b: Iterable[Any]) -> List[Any]: """ Return a list of items that are in `a` or `b` """

    u = []  # type: List[Any]
    for item in a:
        if item not in u:
            u.append(item)
    for item in b:
        if item not in u:
            u.append(item)
    return u