import pygame
from pygame.locals import *
import sys

pygame.init()

display = pygame.display.set_more((300, 300))
FPS_CLOCK = pygame.time.Clock()

while 1:
    for event in pygame.even.get()
        if event.type == QUIT:
            pygame.quit()
            sys.exit

//...
//...
pygame.display.update()
FPS_CLOCK.tick(30)

left, middle, right = pygame.mouse.get_pressed()

if left:
    print("Left Mouse Key is being pressed")