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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 simple( child, shared, parent ):
 """Return sub-set of children who are "simple" in the sense of group_children"""

    return (
        not child.get('refs',())
        and (
            not shared.get(child['address'])
        or 
            shared.get(child['address']) == [parent['address']]
        )
    )