def createPlot():
    fig = plt.figure(1, facecolor = 'white')
    fig.clf()
    createPlot.ax1 = plt.subplot(111, frameon = False)
    plotNode('nonLeafNode', (0.2, 0.1), (0.4, 0.8), nonLeafNodes)
    plotNode('LeafNode', (0.8, 0.1), (0.6, 0.8), leafNodes)
    plt.show()

createPlot()

代码里的createPlot.ax1是什么意思？之前没见过这么用过，请教了！