如何在鼠标单击时在FigureCanvasQTAgg上绘制圆圈

import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import Qt

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

        self.figure = plt.figure()
        self.canvas = FigureCanvas(self.figure)
        self.setCentralWidget(self.canvas)

    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:
            x = event.pos().x()
            y = event.pos().y()
            self.draw_circle(x, y)

    def draw_circle(self, x, y):
        circle = plt.Circle((x, y), 10, color='r')
        self.figure.gca().add_artist(circle)
        self.canvas.draw()

if __name__ == '__main__':
    app = QApplication([])
    window = MyWindow()
    window.show()
    app.exec_()