如何从PYQT4中的类中调用函数

import sys
from PyQt4.QtGui import QApplication, QMainWindow, QPushButton

class MyWindow(QMainWindow):
    def __init__(self):
        super(MyWindow, self).__init__()
        self.initUI()

    def initUI(self):
        self.setGeometry(100, 100, 300, 200)
        self.setWindowTitle('Function Call Example')

        button = QPushButton('Click me', self)
        button.clicked.connect(self.myFunction)
        button.move(100, 100)

    def myFunction(self):
        print('Button clicked!')

if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = MyWindow()
    window.show()
    sys.exit(app.exec_())