def convert_value_to_text value, crow
      case value
      when TrueClass, FalseClass
        value
      else
        value.to_s if value
      end
    end
def convert_value_to_text value, crow
      case value
      when TrueClass, FalseClass
        value
      else
        value.to_s if value
      end
    end
the idea here is to allow users who subclass Listbox to easily override parts of the cumbersome repaint
 method. This assumes your List has some data, but you print a lot more. Now you don't need to
 change the data in the renderer, or keep formatted data in the list itself.
 e.g. @list contains file names, or File objects, and this converts to a long listing.
 If the renderer did that, the truncation would be on wrong data.
 @since 1.2.0