code: def td_contents(self, item, attr_list):
          
          return self.td_format(self.from_attr_list(item, attr_list))
docs: Given an item and an attr, return the contents of the td.
  
          This method is a likely candidate to override when extending
          the Col class, which is done in LinkCol and
          ButtonCol. Override this method if you need to get some extra
          data from the item.
  
          Note that the output of this function is NOT escaped.