如何在QComboBox列表中居中显示文本？

pip install PyQt5

import sys
from PyQt5.QtWidgets import QApplication, QComboBox, QWidget, QVBoxLayout
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QFontMetrics, QStyledItemDelegate

class CenterTextDelegate(QStyledItemDelegate):
    def initStyleOption(self, option, index):
        super().initStyleOption(option, index)
        option.displayAlignment = Qt.AlignCenter

class CenterTextComboBox(QComboBox):
    def __init__(self):
        super().__init__()
        self.setItemDelegate(CenterTextDelegate())

app = QApplication(sys.argv)

window = QWidget()
layout = QVBoxLayout()

combo_box = CenterTextComboBox()
combo_box.addItem("Item 1")
combo_box.addItem("Item 2")
combo_box.addItem("Item 3")

layout.addWidget(combo_box)
window.setLayout(layout)
window.show()

sys.exit(app.exec_())