How to hide a window in the constructor?

I wanna hide a window at once it creates. It works only if I do this with the help of button or something.

    class Example(QWidget):
        def __init__(self, parent=None):
            super(Example, self).__init__(parent)
            self.hide() # doesn't work
            self.btn = QPushButton('Hide', self)
            self.btn.clicked.connect(self.click) # works
            self.btn.show()

        def click(self): # works
            self.hide()