How do I get python to choose a random coordinate to choose the position of a turtle circle?

How do I get a python turtle circle to choose it's position randomly? Here is my code for one circle

asteroid.pencolor('white')
asteroid.fillcolor('grey')
asteroid.begin_fill()
asteroid.hideturtle()
asteroid.penup()
asteroid.speed(11)
asteroid.setposition(350,-200)
asteroid.pendown()
asteroid.circle(40)
asteroid.end_fill()