为什么说在函数pygame中未定义左上角？

我正在使用Python 2.7，也正在使用Pygame。我一直想旋转图像，这就是到目前为止。

import pygame, random
from random import randint
# add parking lot, hunger bar, water bar, shops, drive-thrus, etc...
# add AI car/cars, police cars when going over 30 speed at the road(5 speed in parking lot/drive thru), does not crash when hitting building/other cars(only gets hit back)
# make turning animation
pygame.init()

done = False

x = 465
when = 0
road_stripe_y = 0
road_stripe_y2 = 250
road_stripe_y3 = 500
road_stripe_y4 = 700
speed = 0
gear = 1
ai_car_y = 0
parking_lot_y = -400
player_angle = 0

ground = (50, 100, 0)
road = (64, 64, 64)
black = (0, 0, 0)
white = (255, 255, 255)

screen = pygame.display.set_mode((1000, 800))
screen.fill(ground)

player = pygame.image.load('racing car copy.png')
ai_car = pygame.image.load('ai_racing car.png')
road_stripe = pygame.image.load('costume1 copy.png')

font = pygame.font.Font('freesansbold.ttf', 40)
text = font.render('Gear', True, black, ground)
text2 = font.render(str(gear), True, black, ground)
text2_rect = text2.get_rect()
text_rect = text.get_rect()
text_rect.center = (100, 100)
text2_rect.center = (100, 150)

screen.blit(player, (x, 600))
clock = pygame.time.Clock()

def rotate(screen, player, topleft, player_angle):
    rotated_player = pygame.transform.rotate(player, player_angle)
    new_player_rect = rotated_player.get_rect(center = player.get_rect(topleft = topleft).center)
    screen.blit(rotated_player, new_player_rect.topleft)

while not done == True:
    global gear
    global left
    global right
    pygame.event.get()
    pygame.display.flip()
    pressed = pygame.key.get_pressed()
    if pressed[pygame.K_ESCAPE]:
        done = True
    if pressed[pygame.K_a]:
        if not x >= 670 and not speed == 0:
            x += speed/4
    if pressed[pygame.K_d] and not speed == 0:
        if not x <= 280:
            x -= speed/4
    rotate(screen, player, topleft, player_angle)
    player_collison_box = player.get_rect(topleft=(x, 600))
    if pressed[pygame.K_w]:
        if not speed >= 5 and gear == 1:
            speed += 1
        elif not speed >= 15 and gear == 2:
            speed += 1
        elif not speed >= 30 and gear == 3:
            speed += 1
        elif not speed >= 40 and gear == 4:
            speed += 1
        elif not speed >= 80 and gear == 5:
            speed += 1
    else:
        if not speed <= 0:
            speed -= 1
    if speed >= 15 and gear == 2:
        speed -= 1
    if speed >= 5 and gear == 1:
        speed -= 1
    if speed >= 30 and gear == 3:
        speed -= 1
    if speed >= 40 and gear == 4:
        speed -= 1
    if speed >= 80 and gear == 5:
        speed -= 1
    if pressed[pygame.K_1]:
        gear = 1
    elif pressed[pygame.K_2]:
        gear = 2
    elif pressed[pygame.K_3]:
        gear = 3
    elif pressed[pygame.K_4]:
        gear = 4
    elif pressed[pygame.K_5]:
        gear = 5
    screen.fill(ground)
    pygame.draw.rect(screen, road, (240 + x - 465, 0, 500, 1000))
    parking_lot_y += speed
    pygame.draw.rect(screen, road, (400, parking_lot_y, 600, 800))
    screen.blit(road_stripe, (490 + x - 465, road_stripe_y))
    screen.blit(road_stripe, (490 + x - 465, road_stripe_y2))
    screen.blit(road_stripe, (490 + x - 465, road_stripe_y3))
    screen.blit(road_stripe, (490 + x - 465, road_stripe_y4))
    road_stripe_y += speed
    road_stripe_y2 += speed
    road_stripe_y3 += speed
    road_stripe_y4 += speed
    if road_stripe_y >= 850:
        road_stripe_y = -100
    if road_stripe_y2 >= 850:
        road_stripe_y2 = -100
    if road_stripe_y3 >= 850:
        road_stripe_y3 = -100
    if road_stripe_y4 >= 850:
        road_stripe_y4 = -100
    ai_car_y += speed + 30
    if ai_car_y >= 3000:
        ai_car_y = -100
    screen.blit(player, (465, 600))
    text2 = font.render(str(gear), True, black, ground)
    screen.blit(text, text_rect)
    screen.blit(text2, text2_rect)
    screen.blit(ai_car, (325 + x - 465, ai_car_y))
    clock.tick(40)

pygame.quit()

这就是所谓的函数：

rotate(screen, player, topleft, player_angle)

我不知道问题是什么，但是它说“ topleft”没有定义。确实令人困惑，因为在导入Pygame时不应该单独定义topleft吗？我在互联网上找不到任何有用的答案，所以您可以帮我吗？