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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 with_timestamps(self, created_at=None, updated_at=None):
 """ Specify that the pivot table has creation and update columns. """

        if not created_at:
            created_at = self.created_at()

        if not updated_at:
            updated_at = self.updated_at()

        return self.with_pivot(created_at, updated_at)