human
Write me a Python code to fix the code below to make the ball move! given the following:
I am working on the file ".ipynb_checkpoints/Python_Basics-checkpoint.ipynb".
The first task is:
Okay, now the properties of the ball are set. It has a position represented by a list with an x and y coordinate. You can also think of this list as a vector. So far, you have set the x value to 0 and the y value to 1. This means, the ball is floating in a height of 1 (meter). The ball's velocity is also a vector which, so far, only contains zeros.
A ball floating in a height of 1 meter is not very realistic. The ball should be able to move! We assume that there is no friction. The only thing that changes the velocity of the ball is the gravitational force. To make the ball move you have to:
1. Update the position of the ball. We will do that be adding the velocity multiplied with time step. This is not absolutely correct because the velocity is not constant during a step. However, if we keep the step size reasonably small we should be fine.
2. Update the velocity of the ball. 
Fix the code below to make the ball move!
Can you write Python code for it?
assistant
#Here is Python code to fix the code below to make the ball move!
.

class Ball:
    def __init__(self, start_position, start_velocity, radius):
        self.position = start_position
        self.velocity = start_velocity
        self.radius = radius
    
    # so for the move function doesn't change anything. Fix it!
    def move(self, time_step):
        self.position[0] += 0
        self.position[1] += 0
        
        self.velocity[0] += 0
        self.velocity[1] += 0
        
tennis_ball = Ball([0, 1], [0, 0], 0.033)
time_step = 0.04

for step in range(1, 15): # range is a built-in function which returns all number is a given range
    tennis_ball.move(time_step)
    print('time:', step*time_step, 'position:', tennis_ball.position)