如何在QTreeWidget中检查标志的状态？

from PyQt5.QtWidgets import QApplication, QTreeWidget, QTreeWidgetItem, QMainWindow, QWidget, QVBoxLayout
from PyQt5.QtCore import Qt

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()

        # 创建一个QTreeWidget
        self.treeWidget = QTreeWidget()
        self.treeWidget.setHeaderLabels(["Item", "Flag"])

        # 添加一些树节点
        root = QTreeWidgetItem(self.treeWidget, ["Root", ""])
        child1 = QTreeWidgetItem(root, ["Child 1", ""])
        child2 = QTreeWidgetItem(root, ["Child 2", ""])
        child3 = QTreeWidgetItem(root, ["Child 3", ""])

        # 设置标志的状态
        child1.setCheckState(0, Qt.Checked)
        child2.setCheckState(0, Qt.Unchecked)
        child3.setCheckState(0, Qt.PartiallyChecked)

        # 将QTreeWidget添加到主窗口
        centralWidget = QWidget(self)
        layout = QVBoxLayout(centralWidget)
        layout.addWidget(self.treeWidget)
        self.setCentralWidget(centralWidget)

        # 检查标志的状态
        self.checkFlagState()

    def checkFlagState(self):
        selectedItems = self.treeWidget.selectedItems()
        for item in selectedItems:
            flagState = item.checkState(0)
            if flagState == Qt.Checked:
                print("标志已选中")
                # 执行相应操作
            elif flagState == Qt.Unchecked:
                print("标志未选中")
                # 执行相应操作
            elif flagState == Qt.PartiallyChecked:
                print("标志部分选中")
                # 执行相应操作

if __name__ == "__main__":
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()