如何在PyQt5中设置QTableWidget单元格的样式？

from PyQt5.QtWidgets import QApplication, QTableWidget, QStyledItemDelegate, QColorDialog, QVBoxLayout, QWidget
from PyQt5.QtGui import QColor, QPainter
from PyQt5.QtCore import Qt


class CustomDelegate(QStyledItemDelegate):
    def createEditor(self, parent, option, index):
        # 创建编辑器，这里使用QColorDialog作为示例
        editor = QColorDialog(parent)
        return editor

    def setEditorData(self, editor, index):
        # 设置编辑器的初始值
        value = index.data(Qt.DisplayRole)
        if value is not None and isinstance(value, QColor):
            editor.setCurrentColor(value)

    def setModelData(self, editor, model, index):
        # 将编辑器中的数据写入模型
        model.setData(index, editor.currentColor(), Qt.DisplayRole)

    def paint(self, painter, option, index):
        # 绘制单元格的样式
        if option.state & QStyle.State_Selected:
            painter.fillRect(option.rect, option.palette.highlight())
        else:
            painter.fillRect(option.rect, QColor(255, 255, 255))

        # 绘制文本
        value = index.data(Qt.DisplayRole)
        if value is not None and isinstance(value, QColor):
            painter.setPen(Qt.NoPen)
            painter.setBrush(value)
            painter.drawEllipse(option.rect.center(), 10, 10)

    def sizeHint(self, option, index):
        # 设置单元格大小
        return QSize(20, 20)


if __name__ == '__main__':
    import sys

    app = QApplication(sys.argv)

    table_widget = QTableWidget(4, 4)
    table_widget.setItemDelegate(CustomDelegate())

    for row in range(table_widget.rowCount()):
        for column in range(table_widget.columnCount()):
            item = QTableWidgetItem()
            item.setData(Qt.DisplayRole, QColor(255, 0, 0))
            table_widget.setItem(row, column, item)

    widget = QWidget()
    layout = QVBoxLayout(widget)
    layout.addWidget(table_widget)
    widget.show()

    sys.exit(app.exec_())