code: def drawItem(self, item, painter, option):
          
          dataset = item.dataset()
          
          painter.save()
          painter.setRenderHint(painter.Antialiasing)
          
          pen = QPen(dataset.color())
          pen.setWidth(3)
          painter.setPen(pen)
          painter.setBrush(Qt.NoBrush)
          painter.drawPath(item.path())
          
          if self.showPoints():
              palette = QApplication.palette()
              pen = QPen(palette.color(palette.Base))
              pen.setWidth(2)
              
              painter.setBrush(dataset.color())
              painter.setPen(pen)
              
              for point in item.buildData('ellipses', []):
                  painter.drawEllipse(point,
                                      self.pointRadius(),
                                      self.pointRadius())
          
          painter.restore()
docs: Draws the inputed item as a bar graph.
          
          :param      item    | <XChartDatasetItem>
                      painter | <QPainter>
                      option  | <QStyleOptionGraphicsItem>