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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 fullyflatten(container):
 """ Completely flattens out a cluster and returns a one-dimensional set containing the cluster's items. This is useful in cases where some items of the cluster are clusters in their own right and you only want the items. :param container: the container to flatten. """

    flattened_items = []

    for item in container:
        if hasattr(item, 'items'):
            flattened_items = flattened_items + fullyflatten(item.items)
        else:
            flattened_items.append(item)

    return flattened_items