import signal, turtle

def timeout_handler(signal, frame): # End of timer function
    raise Exception('Time is up!')

signal.signal(signal.SIGALRM, timeout_handler)
signal.alarm(10) # Number inside is how long the game will last.

def hit_a():
    print("a registered")
def hit_b():
    print("b registered")
def hit_c():
    print("c registered")
def hit_d():
    print("d registered")
def hit_e():
    print("e registered")
def hit_f():
    print("f registered")

turtle.onkey(hit_a, "a")
turtle.onkey(hit_b, "b")
turtle.onkey(hit_c, "c")
turtle.onkey(hit_d, "d")
turtle.onkey(hit_e, "e")
turtle.onkey(hit_f, "f")
turtle.listen()


while True:
    pass
    # Add program here
turtle.mainloop()

from turtle import Screen, Turtle

def timeout_handler():
    raise Exception('Time is up!')  # this may need some tweaking

def hit_a():
    print("a registered")

def hit_b():
    print("b registered")

def hit_c():
    print("c registered")

def hit_d():
    print("d registered")

def hit_e():
    print("e registered")

def hit_f():
    print("f registered")

screen = Screen()
turtle = Turtle()

screen.onkey(hit_a, "a")
screen.onkey(hit_b, "b")
screen.onkey(hit_c, "c")
screen.onkey(hit_d, "d")
screen.onkey(hit_e, "e")
screen.onkey(hit_f, "f")

screen.listen()
screen.ontimer(timeout_handler, 10000)  # 10 seconds from now
screen.mainloop()