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