如何使用自定义上下文菜单编辑QListwidgetItem？

from PyQt5.QtWidgets import QApplication, QListWidget, QListWidgetItem, QMenu, QAction
from PyQt5.QtCore import Qt

def edit_item():
    selected_items = list_widget.selectedItems()
    if selected_items:
        item = selected_items[0]
        # 编辑选中的QListWidgetItem
        # ...

def delete_item():
    selected_items = list_widget.selectedItems()
    if selected_items:
        item = selected_items[0]
        # 删除选中的QListWidgetItem
        # ...

app = QApplication([])
list_widget = QListWidget()

# 创建上下文菜单
context_menu = QMenu(list_widget)
edit_action = QAction("编辑", list_widget)
delete_action = QAction("删除", list_widget)
context_menu.addAction(edit_action)
context_menu.addAction(delete_action)

# 关联上下文菜单
list_widget.setContextMenuPolicy(Qt.CustomContextMenu)

# 实现槽函数
edit_action.triggered.connect(edit_item)
delete_action.triggered.connect(delete_item)

# 显示上下文菜单
def show_context_menu(position):
    context_menu.exec_(list_widget.mapToGlobal(position))

list_widget.customContextMenuRequested.connect(show_context_menu)

# 添加示例数据
item1 = QListWidgetItem("Item 1")
item2 = QListWidgetItem("Item 2")
list_widget.addItem(item1)
list_widget.addItem(item2)

list_widget.show()
app.exec_()