Drawing rectangles with Pygame

import pygame
import random
import time

# Define some colors
BLACK = (0, 0, 0)
WHITE = (255, 255, 255)
GREEN = (0, 255, 0)
RED = (255, 0, 0)


class Rectangle():
    '''Draw a rectangle'''
    def __init__(self):
        '''These are the rectangle's attributes.'''
        self.x = 0
        self.y = 0
        self.width = 0
        self.height = 0
        self.change_x = 0
        self.change_y = 0
        self.color = [0, 0, 0]

    def draw(self, screen):
        '''Drawing the rectangle.'''
        pygame.draw.rect(screen, self.color, [self.x, self.y, self.width, self.height])

    def move(self):
        '''Moving the rectangle around the screen.'''
        self.x += self.change_x
        self.y += self.change_y


def main():
    pygame.init()

    # Set the width and height of the screen [width, height]
    size = (700, 500)
    screen = pygame.display.set_mode(size)

    pygame.display.set_caption("My Game")

    # Loop until the user clicks the close button.
    done = False

    # Used to manage how fast the screen updates
    clock = pygame.time.Clock()

    my_list = []
    color_list = []
    '''Creates 1000 rectangles.'''
    for i in range(2000):
        my_object = Rectangle()

        r = random.randrange(256)
        g = random.randrange(256)
        b = random.randrange(256)
        my_object.color = [r, g, b]
        color_list.append(my_object)

        my_object.x = random.randrange(701)
        my_object.y = random.randrange(501)

        my_object.change_x = random.randrange(-3, 4)
        my_object.change_y = random.randrange(-3, 4)

        my_object.width = random.randrange(20, 71)
        my_object.height = random.randrange(20, 71)

        my_list.append(my_object)

    # -------- Main Program Loop -----------
    while not done:
        # --- Main event loop
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                done = True

        screen.fill(WHITE)

        # Start the clock
        start = time.time()

        for item in my_list:
            item.draw(screen)
            item.move()

        # --- Go ahead and update the screen with what we've drawn.
        pygame.display.flip()

        # End the clock
        elapsed = time.time() - start
        print(elapsed)

        # --- Limit to 60 frames per second
        clock.tick(60)

    # Close the window and quit.
    pygame.quit()

main()