import os
import signal
import threading


PID = os.getpid()


run = True

def print_hello(*unused_args):
    try:
        print("hello")
    except:
        signal.signal( signal.SIGUSR1, signal.SIG_IGN)
        raise

def send_signals_constantly():
    while run:
        #print("stuff")
        os.kill(PID, signal.SIGUSR1)

def main():
    global run
    signal.signal(signal.SIGUSR1, print_hello)
    t1 = threading.Thread(target=send_signals_constantly)
    t1.start()
    while run:
        try:
            print("world")
        except:
            run = False
            raise

if __name__ == "__main__":
    main()