code: def update_existing_pivot(self, id, attributes, touch=True):
          
          if self.updated_at() in self._pivot_columns:
              attributes = self.set_timestamps_on_attach(attributes, True)
  
          updated = self._new_picot_statement_for_id(id).update(attributes)
  
          if touch:
              self.touch_if_touching()
  
          return updated
docs: Update an existing pivot record on the table.