如何在PySide中为无边框窗体添加最大化、最小化和关闭按钮？

import sys
from PySide6.QtWidgets import QApplication, QMainWindow, QPushButton, QVBoxLayout, QWidget
from PySide6.QtCore import Qt

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

        # 设置无边框
        self.setWindowFlags(Qt.FramelessWindowHint)

        # 创建中心部件以容纳按钮
        central_widget = QWidget()
        self.setCentralWidget(central_widget)

        # 创建布局
        layout = QVBoxLayout(central_widget)

        # 创建按钮
        minimize_button = QPushButton("最小化")
        maximize_button = QPushButton("最大化")
        close_button = QPushButton("关闭")

        # 将按钮添加到布局
        layout.addWidget(minimize_button)
        layout.addWidget(maximize_button)
        layout.addWidget(close_button)

        # 连接按钮点击事件到相应函数
        minimize_button.clicked.connect(self.showMinimized)
        maximize_button.clicked.connect(self.toggleMaximized)
        close_button.clicked.connect(self.close)

    def toggleMaximized(self):
        if self.isMaximized():
            self.showNormal()
        else:
            self.showMaximized()

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = CustomWindow()
    window.show()
    sys.exit(app.exec())