PyQt4 to PyQt5: inheritance issue

I wanted to convert this code snippet to PyQt5. I am running into an issue that I don't understand:

from PyQt5 import QtWidgets
import logging

class QPlainTextEditLogger(logging.Handler):
    def __init__(self, parent):
        super().__init__(parent)


class MyDialog(QtWidgets.QDialog, QPlainTextEditLogger):
    def __init__(self, parent=None):
        super().__init__()    # <= Error here

if (__name__ == '__main__'):
    app = None
    if (not QtWidgets.QApplication.instance()):
        app = QtWidgets.QApplication([])
    dlg = MyDialog()
    dlg.show()
    dlg.raise_()
    if (app):
        app.exec_()

This produces the following error:

super().__init__(parent)
TypeError: __init__() missing 1 required positional argument: 'parent'

Could someone help me?

Thanks!