#functions go here

def yes_no(question):

    """checks user response to a question is yes / no (y/n), returns 'yes' or 'no' """

    while True:

        response = input(question).lower()

        # check the user says yes / no
        if response == " yes" or response == " y":
            return "yes"
        elif response == " no" or response == " n":
            return "no"
        else:
            print("please enter yes /no")


# Main routine

want_instructions = yes_no("do you want to see the instructions")

print("we done")