Pygameで複数のwhileループを同時に実行するにはどうすればよいですか?

<code class="python">import random
import pygame
import pygame.freetype

# Initialize pygame and game variables
face = ['^-^', '^v^', '◠◡◠', "'v'", '⁀◡⁀']
faceDisplay = pygame.freetype.Font('unifont.ttf', 100).render(random.choice(face), 1, (0, 255, 0))
screen = pygame.display.set_mode((800, 600))
run = True

# Variable used to track next face update time
next_render_time = 0

# Main game loop
while run:
    # Handle events (quit, keyboard input, etc.)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    # Calculate current time
    current_time = pygame.time.get_ticks()

    # Check if enough time has passed since the last face update
    if current_time >= next_render_time:
        # Update the displayed face and calculate the next update time
        faceDisplay = pygame.freetype.Font('unifont.ttf', 100).render(random.choice(face), 1, (0, 255, 0))
        next_render_time = current_time + random.randint(5, 10) * 1000  # Generate random time interval

    # Clear the screen, draw the updated face, and flip the display
    screen.fill((0, 0, 0))
    screen.blit(faceDisplay, (screen.get_width() // 2, screen.get_height() // 2))
    pygame.display.flip()</code>