Как написать программу в пайгейм, чтобы после нажатия Alt программа не реагировала на эту клавишу?

import pygame

from Enigma_Keyboard_EN import Keyboard
from Enigma_Plugboard_EN import Plugboard
from Enigma_Reflector_EN import Reflector
from Enigma_Rotors_EN import Rotor
from Enigma_EN import Enigma
from Enigma_Draw_EN import Draw

pygame.init()
pygame.font.init()
pygame.display.set_caption("Enigma_Simulator")

MONO = pygame.font.SysFont("FreeMono", 25)
BOLD = pygame.font.SysFont("FreeMono", 25, bold=True)

WIDTH = 1600
HEIGHT = 900
SCREEN = pygame.display.set_mode((WIDTH, HEIGHT))
MARGINS = {"top": 200, "bottom": 100, "left": 100, "right": 100}
GAP = 100
INPUT = ""
OUTPUT = ""
PATH = []

I = Rotor("EKMFLGDQVZNTOWYHXUSPAIBRCJ", "Q")
II = Rotor("AJDKSIRUXBLHWTMCQGZNPYFVOE", "E")
III = Rotor("BDFHJLCPRTXVZNYEIWGAKMUSQO", "V")
IV = Rotor("ESOVPZJAYQUIRHXLNFTGKDCMWB", "J")
V = Rotor("VZBRGITYUPSDNHLXAWMJQOFECK", "Z")
A = Reflector("EJMZALYXVBWFCRQUONTSPIKHGD")
B = Reflector("YRUHQSLDPXNGOKMIEBFZCWVJAT")
C = Reflector("FVPJIAOYEDRZXWGCTKUQSBNMHL")
KB = Keyboard()
PB = Plugboard(["AR", "GK", "OX"])

ENIGMA = Enigma(B, I, II, III, PB, KB)

ENIGMA.set_ring((1, 1, 1))
ENIGMA.set_key("AAA")

animating = True
while animating:

SCREEN.fill("#333333")

Draw(ENIGMA, PATH, SCREEN, WIDTH, HEIGHT, MARGINS, GAP, BOLD)

text = BOLD.render(INPUT, True, "white")
text_box = text.get_rect(center=(WIDTH / 2, MARGINS["top"] / 3))
SCREEN.blit(text, text_box)

text = MONO.render(OUTPUT, True, "white")
text_box = text.get_rect(center=(WIDTH / 2, MARGINS["top"] / 3 + 25))
SCREEN.blit(text, text_box)

pygame.display.flip()

for event in pygame.event.get():
if event.type == pygame.QUIT:
animating = False
elif event.type == pygame.KEYDOWN:
if event.key == pygame.K_DOWN:
II.rotate()
elif event.key == pygame.K_SPACE:
INPUT = INPUT + " "
OUTPUT = OUTPUT + " "
else:
key = event.unicode
if key in "abcdefghijklmnopqrstuvwxyz":
letter = key.upper()
INPUT = INPUT + letter
PATH, cipher = ENIGMA.encipher(letter)
OUTPUT = OUTPUT + cipher