The circle animation is not displayed with the following code in anaconda spyder. Why?

Question

The circle animation is not displayed with the following code in anaconda spyder. Why?

The code is given below.

from matplotlib import pyplot as plt
from matplotlib import animation

def create_circle():
    circle = plt.Circle((0, 0), 0.05)
    return circle

def update_radius(i, circle):
    circle.radius = i*0.5
    return circle,

def create_animation():
    fig = plt.gcf()
    ax = plt.axes(xlim=(-10, 10), ylim=(-10, 10))
    ax.set_aspect('equal')
    circle = create_circle()
    ax.add_patch(circle)
    anim = animation.FuncAnimation(fig, update_radius, fargs = (circle,), frames=30, interval=50)
    plt.title('Simple Circle Animation')
    plt.show()

if __name__ == '__main__':
    create_animation()