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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 flatten(items):
 """ Yield items from any nested iterable. [1, 2, 3, 4, 5, 6, 7] """

    for x in items:
        if isinstance(x, Iterable) and not isinstance(x, (str, bytes)):
            for sub_x in flatten(x):
                yield sub_x
        else:
            yield x