How to set framerate in Pygame?

So in response to my question (How to continuously move an image smoothly in Pygame?) I was told to set my framerate in order to do my animation. But no matter where I place it, clock.tick(60) does nothing. I do clock = pygame.time.Clock() BTW. So how do I do this? I have researched and found this (pygame clock.tick() vs framerate in game main loop) but I don’t really understand this.

My main game function;

def main_game():
    global var_escape
    global var_start_game
    global var_menu_screen
    global var_camera
    global var_bounce
    global var_x
    global var_x_timer
    global var_door
    global var_light
    global camera_flip
    
    var_start_game = False
    var_escape = False
    var_menu_screen = 0
    var_bounce = 0
    var_x = 0
    var_camera = 1
    var_x_timer = 0
    var_light = 0
    var_door = 0
    var_camera_flip = 0
    
    pygame.mixer.init()
    pygame.mixer.music.load(r'audioMenu_Music.mp3')
    pygame.mixer.music.play(-1)

    pygame.mixer.music.set_volume(1.0)

    while True:
        if var_menu_screen == 0:
            menu_screen()
        if var_menu_screen == 1:
            options_screen()
        if var_menu_screen == 2:
            new_game_boyz()
        if var_menu_screen == 3:
            pygame.quit()
            sys.quit()
        if var_menu_screen == 4:
            credits_screen()
        if var_start_game == True:
            break
    
    var_start_game = False
    
    start_game()
    image_door_6_off = pygame.image.load(r'texturesdoorlight offframe_6_off.png')
    image_door_button_off = pygame.image.load(r'texturesdoor buttondoor_button_off.png')
    image_light_button_off = pygame.image.load(r'textureslight buttonlight_button_off.png')
    image_door_6_off_size = image_door_6_off.get_rect().size
    centered_image_door_6_off = [(display_size[0] - image_door_6_off_size[0])/2, (display_size[1] - image_door_6_off_size[1])/2]
    screen.blit(image_door_6_off, centered_image_door_6_off)
    screen.blit(image_door_button_off, (0, 0))
    screen.blit(image_light_button_off, (1113, 0))
    pygame.display.update()

    while var_escape == False:
#This is my main game loop in the function
#This is where I would like to set the framerate
        mouse_down = False
        for event in pygame.event.get():
            if event.type == pygame.KEYDOWN:
                if event.key == pygame.K_ESCAPE:
                    quit_popup()
            elif event.type == MOUSEBUTTONDOWN:
                mouse_down = True
            
        light(mouse_down)
        door(mouse_down)
        camera_flip()
#Just so I can get a smoother animation for this function below
        cameras() #<--- This function here
#Just so I can get a smoother animation for this function above
        camera_buttons(mouse_down)

This is my main game loop;

while True:     
#Calls the function 
    main_game()

The main game loop will not set the framerate because the main_game function has a loop inside it. This is only in a loop because when I want to restart the function I can. I just added this in to show how the function is run.

Answer

Use pygame.time.Clock to control the frames per second and thus the game speed.

The method tick() of a pygame.time.Clock object, delays the game in that way, that every iteration of the loop consumes the same period of time. See pygame.time.Clock.tick():

This method should be called once per frame.

e.g.:

def main_game():
    # [...]

    FPS = 60
    clock = pygame.time.Clock()
    while var_escape == False:
        clock.tick(60)

        # [...]