如何在Pygame中为单个键改变KMOD状态？

for event in pygame.event.get():
    if event.type == KEYDOWN:
        if event.key == K_LEFT:
            mods = pygame.key.get_mods()
            if mods and KMOD_SHIFT:
                movei = -5
            if mods and KMOD_CTRL:
                movei = -20
            else:
                movei = -10

and

&

if mods and KMOD_SHIFT:

if mods & KMOD_SHIFT:

&

mods