PySide: Load mainwindow from UI file.

mainwindow.pyw

import sys
from PySide.QtCore import QFile
from PySide.QtGui import QApplication, QMainWindow
from PySide.QtUiTools import QUiLoader


class MainWindow(QMainWindow):
    def __new__(cls, *args, **kwargs):
        """Load widget from UI file."""
        super().__new__(cls, *args, **kwargs)
        uifile = QFile('mainwindow.ui')
        uifile.open(QFile.ReadOnly)
        mainWindow = QUiLoader().load(uifile)
        uifile.close()

        return mainWindow


if __name__ == "__main__":
    app = QApplication(sys.argv)
    mainWindow = MainWindow()
    mainWindow.show()
    sys.exit(app.exec_())

`
Traceback (most recent call last):

File "_run.py", line 29, in

mainWindow = MainWindow()

File "_run.py", line 18, in new

super().__new__(cls, *args, **kwargs)

TypeError: super() takes at least 1 argument (0 given)
`