I want to make sure the following code runs only twice.

I'm making a drone simulator. And I was making a program in Python tkinter to make a drone move between two points using a canvas. I am asking this question because I would like to take pictures only twice rather than taking pictures of two points indefinitely. I used unbind but it didn't work. I tried using methods other than stop() to terminate the function, but it didn't work. It's very difficult because Python is not my main skill. help.

code :
def start_point(event):
x1, y1 = ( event.x-1 ), ( event.y-1 )
x2, y2 = ( event.x+1 ), ( event.y+1 )
canvas.create_oval(x1, y1, x2, y2,width=10, fill='blue', outline='blue')

canvas.bind("", start_point,add='')