code: def headerData(self, section, orientation, role=Qt.DisplayRole):
          
          if role != Qt.DisplayRole:
              return None
          if orientation == Qt.Vertical:
              return six.text_type(self.color_da.cmap[section].values)
          return super(ColormapModel, self).headerData(section, orientation,
                                                       role)
docs: Set header data