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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 users(self):
 """Returns a GroupUsersCursor with list of User instances for this Group .. versionadded:: 2.16.2 """

        if self.__users is None:
            self.__users = GroupUsersCursor(swimlane=self._swimlane, user_ids=self.__user_ids)
        return self.__users