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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 classes_(self):
 """ Proxy property to smartly access the classes from the estimator or stored locally on the score visualizer for visualization. """

        if self.__classes is None:
            try:
                return self.estimator.classes_
            except AttributeError:
                return None
        return self.__classes