问当使用模块tkinter中的create_oval()方法时，如何标记所绘制的每个圆圈？

EN

import tkinter as tk

WIDTH, HEIGHT = 200, 200

root = tk.Tk()

canvas = tk.Canvas(root, width=WIDTH, height=HEIGHT)
canvas.pack()

x0, y0, x1, y1 = 50, 50, 100, 100
canvas.create_oval(x0, y0, x1, y1, outline='black')

center_x, center_y = (x0+x1)/2, (y0+y1)/2
canvas.create_text(center_x, center_y, text='Label')

root.mainloop()

import tkinter as tk

if __name__ == '__main__':

    root = tk.Tk()
    canvas = tk.Canvas(root, width=200, height=200, bg='cyan')
    canvas.pack()
    x0, y0, x1, y1 = 25, 25, 75, 75

    circle_A = canvas.create_oval(x0, y0, x1, y1)
    canvas.create_text(canvas.coords(circle_A)[:2], text='A')

    x0, y0, x1, y1 = 125, 125, 175, 175
    circle_B = canvas.create_oval(x0, y0, x1, y1)
    canvas.create_text(canvas.coords(circle_B)[2:], text='B')

    root.mainloop()