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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 pick(self, *args):
 """ Return a copy of the object only containing the whitelisted properties. """

        ns = self.Namespace()
        ns.result = {}

        def by(key, *args):
            if key in self.obj:
                ns.result[key] = self.obj[key]

        _.each(self._flatten(args, True, []), by)
        return self._wrap(ns.result)