Pygame - Collision of 3 graphics: AttributeError: 'tuple' object has no attribute 'collidepoint'

Question

I'm currently trying to program a Pong clone, but I can't manage to integrate the collisions with graphics. There are 3 graphics in the game:

• Graphic for player 1
• Graphic for player 2
• Graphic for the playing ball

I read somewhere that I have to convert the graphs into rectangles and then build in the collisions based on the diameter of the 3 graphics. Unfortunately, I get the following error message:

Traceback (most recent call last):
  File "C:\Users\...Pong.py", line 67, in <module>
    if image_ball_center.collidepoint(image_player1_center):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'tuple' object has no attribute 'collidepoint'

How can I install the collisions correctly? Does anyone have any ideas? That is my source code:

import pygame

pygame.init()

WIDTH = 1280
HEIGHT = 720

screen = pygame.display.set_mode((WIDTH,HEIGHT))
background_image = pygame.image.load("sky.jpg")

tennisball = pygame.image.load("tennisball.png")
player1 = pygame.image.load("player1.jpg")
player2 = pygame.image.load("player2.jpg")

x1 = 80
y1 = 300

x2 = 1200
y2 = 300

tennisball_x = 650
tennisball_y = 300

movement_x = 1
movement_y = 1

running = True
while (running):

    for event in pygame.event.get():

        if event.type == pygame.QUIT:
            running = False

    keys = pygame.key.get_pressed()

    if keys[pygame.K_UP]:
        y1 = y1 - 2
    if keys[pygame.K_DOWN]:
        y1 = y1 + 2

    if keys[pygame.K_s]:
        y2 = y2 + 2
    if keys[pygame.K_w]:
        y2 = y2 - 2

    tennisball_x = tennisball_x + movement_x
    tennisball_y = tennisball_y + movement_y

    if tennisball_y > HEIGHT or tennisball_y < 0:
        movement_y = movement_y * -1

    if tennisball_x > WIDTH or tennisball_x < 0:
        movement_x = movement_x * -1

    image_ball = tennisball
    rect = image_ball.get_rect()
    image_ball_center = rect.center

    image_player1 = player1
    rect2 = image_player1.get_rect()
    image_player1_center = rect2.center

    if image_ball_center.collidepoint(image_player1_center):
        movement_x = movement_x * -1

    screen.blit(background_image, (0,0))

    screen.blit(tennisball,(tennisball_x,tennisball_y))
    screen.blit(player1,(x1,y1))
    screen.blit(player2, (x2, y2))

    pygame.display.update()
pygame.quit()