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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 get_shorty_idx_value(self):
 """ Return the string associated to the shorty_idx :rtype: string """

        if self.shorty_idx_value == None:
            self.shorty_idx_value = self.CM.get_string(self.shorty_idx)
        return self.shorty_idx_value