inter.py

def get_a():
    print 10


def get_b():
    print 12


def get_c():
    print 13

if __name__ == "__main__":
    while True:
        try:
            input(">>")()
        except NameError as ex:
            print("This function is not defined!")
        except KeyboardInterrupt:
            print("Exiting...")
            break