stackoverflow found the processing of logging

but copying the original code will prompt

QObject::connect: Cannot queue arguments of type "QTextBlock"
(Make sure "QTextBlock" is registered using qRegisterMetaType().)
QObject::connect: Cannot queue arguments of type "QTextCursor"
(Make sure "QTextCursor" is registered using qRegisterMetaType().)

follow the search and find the safer way to modify the user interface is to send a signal signal to the UI window

to sum up, the code is as follows

class MyThead(QtCore.QThread):
    updated = QtCore.pyqtSignal(str)
    
    def __init__(self, mainUI, msg):
        super().__init__()
        self.updated.connect(mainUI.plainTextEdit.appendPlainText)
        self.msg = msg

    def run(self):
        self.updated.emit(self.msg)

class QPlainTextEditLogger(logging.Handler):

    def __init__(self, mainUI):
        super().__init__()
        self.mainUI = mainUI

    def emit(self, record):
        msg = self.format(record)
        _thread = MyThead(self.mainUI, msg)
        _thread.start()

code cannot be executed, the window is destroyed directly, and no error is reported