pyqt 关闭事件的问题 AttributeError: 'RegisterWindow' object has no attribute 'closed'. Did you mean: 'close'?

self.registerWin.closed.connect(self.on_reg_window_closed) 这行代码运行的时候报错 AttributeError: 'RegisterWindow' object has no attribute 'closed'. Did you mean: 'close'?

RegisterWindow 继承于 QWidget class RegisterWindow(QWidget):

就是现在如果我想实现子窗口打开的时候主窗口隐藏, 反之显示, 所以这里需要用一个子窗口的关闭事件, 但是出现这个问题如何解决?

# -*- coding: utf-8 -*-
from PyQt6.QtWidgets import QApplication, QWidget, QLabel, QLineEdit, QPushButton, QVBoxLayout
from registerWindow import RegisterWindow
from PyQt6 import QtCore, QtWidgets


class LoginWindow(QWidget):
    def __init__(self):
        super().__init__()

        # 设置窗口大小
        self.setGeometry(200, 200, 400, 200)

        # 创建控件
        self.username_label = QLabel('用户名')
        self.username_input = QLineEdit()
        self.password_label = QLabel('密码')
        self.password_input = QLineEdit()
        self.login_button = QPushButton('登录')
        self.register_button = QPushButton('注册')

        # 创建布局
        layout = QVBoxLayout()
        layout.addWidget(self.username_label)
        layout.addWidget(self.username_input)
        layout.addWidget(self.password_label)
        layout.addWidget(self.password_input)
        layout.addWidget(self.login_button)
        layout.addWidget(self.register_button)

        # 设置布局
        self.setLayout(layout)

        # 子窗口
        self.registerWin = RegisterWindow()
        self.registerWin.closed.connect(self.on_reg_window_closed)

        # 连接信号和槽
        self.login_button.clicked.connect(self.on_login_button_clicked)
        self.register_button.clicked.connect(self.on_register_button_clicked)

    def on_sub_window_closed(self):
        # 子窗口已关闭
        print("子窗口已关闭")

    def on_login_button_clicked(self):
        username = self.username_input.text()
        password = self.password_input.text()

        # 在这里可以添加验证用户输入的代码，如果验证通过则可以跳转到主界面

    def on_register_button_clicked(self):
        self.hide()
        self.registerWin.show()

    def on_reg_window_closed(self):
        self.show()


if __name__ == '__main__':
    app = QApplication([])
    login_window = LoginWindow()
    login_window.show()
    app.exec()