如何在浮动的QDockWidget中添加最大化按钮？

from PyQt5.QtWidgets import QMainWindow, QDockWidget, QWidget, QVBoxLayout, QPushButton, QApplication
from PyQt5.QtCore import Qt

class CustomDockWidget(QDockWidget):
    def __init__(self, title, parent=None):
        super().__init__(title, parent)
        
        # 创建标题栏部件
        title_widget = QWidget()
        title_layout = QVBoxLayout(title_widget)
        title_layout.setContentsMargins(0, 0, 0, 0)
        title_layout.setAlignment(Qt.AlignLeft)
        
        # 创建最大化按钮
        maximize_button = QPushButton()
        maximize_button.setIcon(QIcon("maximize_icon.png"))
        maximize_button.clicked.connect(self.toggleMaximized)
        
        # 将最大化按钮添加到标题栏布局中
        title_layout.addWidget(maximize_button)
        
        # 设置标题栏部件
        self.setTitleBarWidget(title_widget)
        
    def toggleMaximized(self):
        if self.isFloating():
            self.setFloating(False)
        else:
            self.setFloating(True)

# 创建主窗口
app = QApplication([])
main_window = QMainWindow()

# 创建自定义的QDockWidget
dock_widget = CustomDockWidget("My Dock Widget")
main_window.addDockWidget(Qt.LeftDockWidgetArea, dock_widget)

# 显示主窗口
main_window.show()
app.exec_()