如何在PyQt5 Python中添加正确的标记或错误的标记

from PyQt5.QtWidgets import QApplication, QMainWindow, QLineEdit
from PyQt5.QtGui import QIntValidator

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        
        self.line_edit = QLineEdit(self)
        self.line_edit.setValidator(QIntValidator(0, 100, self))  # 设置验证器
        
        self.setCentralWidget(self.line_edit)

if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()

from PyQt5.QtWidgets import QApplication, QMainWindow, QLineEdit

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        
        self.line_edit = QLineEdit(self)
        
        self.setCentralWidget(self.line_edit)
        
        self.line_edit.textChanged.connect(self.validate_input)
    
    def validate_input(self, text):
        if not text.isdigit():  # 判断输入是否为数字
            self.line_edit.setStyleSheet("QLineEdit { background-color: red; }")  # 设置错误的样式
        else:
            self.line_edit.setStyleSheet("")  # 清除错误的样式

if __name__ == '__main__':
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()