code: def dragData(self, x=None, y=None):
          
          # look for specific drag information for this item
          first  = (x, y)
          second = (x, None)
          third  = (None, y)
          fourth = (None, None)
          
          for key in (first, second, third, fourth):
              data = self._dragData.get(key)
              if data:
                  return data
          
          return None
docs: Returns any drag information that will be used from this chart item.
          
          :return     <QMimeData> || None