code: def mouseDoubleClickEvent(self, ev):
      print("anning", self.anning)
      if self.anning:
          self.setPen(QtGui.QPen(self.color, self.width))
          self.polygon_item.addPointMiddle(self.idx, ev.pos())
      super(LineItem, self).mouseDoubleClickEvent(ev)
  
file_path: PaddleSeg/EISeg/eiseg/widget/line.py
imports: from qtpy import QtWidgets, QtGui, QtCore
label_desc: Use image node_id 8 for calling the LineItem obj's underlying member method code with example usage: obj.mouseDoubleClickEvent(ev) without return types