Python draw animation through matplotlib simple example

"""
A simple example of an animated plot
"""
import numpy as np
from matplotlib import pyplot as plt
from matplotlib import animation
# First set up the figure, the axis, and the plot element we want to animate
fig = ()
# create our line object which will be modified in the animation
ax = (xlim=(0, 2), ylim=(-2, 2))
# we simply plot an empty line: we'll add data to the line later
line, = ([], [], lw=2) 
# initialization function: plot the background of each frame
def init():
 line.set_data([], [])
 return line,
# animation function. This is called sequentially
# It takes a single parameter, the frame number i 
def animate(i):
 x = (0, 2, 1000)
 y = (2 *  * (x - 0.01 * i)) # update the data
 line.set_data(x, y)
 return line,
# Makes an animation by repeatedly calling a function func
# frames can be a generator, an iterable, or a number of frames.
# interval draws a new frame every interval milliseconds.
# blit=True means only re-draw the parts that have changed.
# Set up a 200-frame animation here, with 20 milliseconds between each frame #
anim = (fig, animate, init_func=init,
        frames=200, interval=20, blit=True)
# save the animation as an mp4. This requires ffmpeg or mencoder to be
# installed. The extra_args ensure that the x264 codec is used, so that
# the video can be embedded in html5. You may need to adjust this for
# your system: for more information, see
# /api/animation_api.html
('basic_animation.mp4', fps=30, extra_args=['-vcodec', 'libx264'])

() # () The animation will keep looping.