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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 is_up_to_date(self):
 """If any child is not up-to-date, then this directory isn't, either."""

        if self.builder is not MkdirBuilder and not self.exists():
            return 0
        up_to_date = SCons.Node.up_to_date
        for kid in self.children():
            if kid.get_state() > up_to_date:
                return 0
        return 1