code: def data(self, index, role=Qt.DisplayRole):
          
          if not index.isValid():
              return to_qvariant()
          if role == Qt.DisplayRole:
              return self._display_data(index)
          elif role == Qt.BackgroundColorRole:
              return to_qvariant(get_color(self._data[index.row()][index.column()], .2))
          elif role == Qt.TextAlignmentRole:
              return to_qvariant(int(Qt.AlignRight|Qt.AlignVCenter))
          return to_qvariant()
docs: Return a model data element