docs: def setDragData(self, format, value):
          """
          Sets the drag information that is associated with this tree
          widget item for the given format.
          
          :param      format | <str>
                      value  | <variant>
          """
          if value is None:
              self._dragData.pop(nativestring(format), None)
          else:
              self._dragData[nativestring(format)] = value