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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 deepvalues(mapping):
 """Iterates over nested mapping, depth-first, in sorted order by key."""

    values = vals_sorted_by_key(mapping)
    for obj in values:
        mapping = False
        try:
            obj.items
        except AttributeError:
            pass
        else:
            mapping = True
            for subobj in deepvalues(obj):
                yield subobj
        if not mapping:
            yield obj