Game Commands

def help():
  print(
    """
start - to start the car
stop  - to stop the car
quit  - to exit
""")  

def start():
  print('Car started...')

def stop():
  print('Car stopped...')

def other():
  print('I don\'t understand')

command = ""
prevCommand = ""

while (command != 'quit'):
  prevCommand = command
  command = input('> ').lower()

  if (command == 'help'):
    help()
  elif (command == 'start'):
    if (prevCommand == 'start'):
      print('The car has already started')
    else:
      start()    
  elif (command == 'stop'):
    if (prevCommand == 'stop'):
      print('The car has already stopped')
    else:
      stop()
  elif (command != 'quit'):
    other()