def yes_no(question):
    """Asks the user a yes or no question"""
    while True:
        reply = raw_input(question + ' (y/n) ').lower()
        if len(reply) == 0 or not ['y', 'n'] in reply[0]:
            continue
        return reply[0] == 'y'
dataset/ETHPy150Open Yelp/paasta/paasta_tools/cli/fsm/prompt.py/yes_no/swapped operands of `in`