PyQt: How to animate dialog size

Question

A code below creates a single QWidget window with QPushButton connected to resizeDialog(). Pressing a button switches a dialog's size from .resize(200,100) to .resize(600,300) and back.

Question: By default the transition from one window's size to another happens instantly. How to override this behavior with an animation?

from PyQt4 import QtCore, QtGui
import sys

class myWindow(QtGui.QWidget):
    def __init__(self, parent=None):
        super(myWindow, self).__init__(parent)
        myLayout = QtGui.QVBoxLayout(self)
        Button = QtGui.QPushButton('Resize')
        myLayout.addWidget(Button)
        Button.setMinimumWidth(200)
        Button.clicked.connect(self.resizeDialog)

    def resizeDialog(self):
        dialog.size().width()==200:
            dialog.resize(600,300)
        else:
            dialog.resize(200,100)

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    app.setApplicationName('myApp')
    dialog = myWindow()
    dialog.resize(200,100)
    dialog.show()
    sys.exit(app.exec_())

Answer 1

def resizeDialog(self):
    self.animation = QtCore.QPropertyAnimation(self, "size")
    # self.animation.setDuration(1000) #Default 250ms
    if self.size().width()==200:
        self.animation.setEndValue(QtCore.QSize(600,300))
    else:
        self.animation.setEndValue(QtCore.QSize(200,100))
    self.animation.start()

The source linked by this question, leads to this code. Translating from the c++ code to python is fairly straight forward in this case.