didnt understand a part of a code in python

Can you please tell me how the 6th line of the following python code.

command = "" started = False while True: command = input("> ") if command == "start": if started: #didnt understand this print("Car already started") else: started = True print("Car started ... ready to go") elif command == "stop": print("Car stopped") elif command == "help": print('''start - to start the stop - to stop the car quit - to exit''') elif command == "quit": break else: print("I don't get it")