Python TypeError: 'function' object is not subscriptable in nested function when i try to implement switch case

I am trying to code a random decision between 3 machines. Since python does not has any switch/case function, i resort to if and elif. Each machine(line1(),line2(),line3() has their own function as well. However I been getting errors.

Please advise me on what is going wrong

machine_choice = [1,2,3]
selected_machine = random.choice(machine_choice)
print(selected_machine)

def machines(selected_machine):
    if selected_machine == 1:
        print("machine 1 randomly selected")
        line1()
    elif selected_machine == 2:
        print("machine 2 randomly selected")
        line2()
    else:
        print("machine 3 randomly selected")
        line3()

machines(selected_machine)