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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 last_change(self):
 """ queries the database for the most recent time an object was either created or updated returns datetime or None if db is empty """

        try:
            cdt = self.latest('created')
            udt = self.latest('updated')
            #print cdt, udt
            return max(cdt.created, udt.updated)

        except ObjectDoesNotExist:
            return None