python pyqt5 QTextEdit 1.文本编辑框应用

from PyQt5.QtWidgets import QApplication, QMainWindow, QAction, QTextEdit
import sys
from PyQt5.QtGui import QIcon, QFont


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

        self.setWindowTitle("文本编辑框")
        self.setGeometry(300, 200, 1000, 600)

        self.textEdit = QTextEdit(self)
        self.textEdit.setFont(QFont('Sanserif', 13))
        self.setCentralWidget(self.textEdit)

        self.setIcon()

        self.create_menu()
        self.show()

    def setIcon(self):
        appIcon = QIcon("icon.png")
        self.setWindowIcon(appIcon)

    def create_menu(self):
        mainMenu = self.menuBar()
        fileMenu = mainMenu.addMenu('File')
        viewMenu = mainMenu.addMenu('View')
        editMenu = mainMenu.addMenu('Edit')
        fontMenu = mainMenu.addMenu('Font')
        helpMenu = mainMenu.addMenu('Help&