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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 once(self):
 """ Returns a function that will be executed at most one time, no matter how often you call it. Useful for lazy initialization. """

        ns = self.Namespace()
        ns.memo = None
        ns.run = False

        def work_once(*args, **kwargs):
            if ns.run is False:
                ns.memo = self.obj(*args, **kwargs)
            ns.run = True
            return ns.memo

        return self._wrap(work_once)