code: def removeLastPoint(self):
      # TODO: 创建的时候用到，需要删line
      if len(self.points) == 0:
          self.points.pop()
          self.setPolygon(QtGui.QPolygonF(self.points))
          if self.bbox:
              self.bbox.update()
          it = self.m_items.pop()
          self.scene().removeItem(it)
          del it
  
imports: from qtpy import QtWidgets, QtGui, QtCore
  from .None import GripItem, LineItem, BBoxAnnotation
label_desc: Use image node_id 9 for calling the PolygonAnnotation obj's underlying member method code with example usage: obj.removeLastPoint() without return types