prompy_yn.py

def prompt_yn(question):
    """
    Prompt the user with a yes or no question.
    
    Input:
        question (str): Question string
    Output:
        answer (bool): Answer True/False
    """
    while True:
        choice = raw_input("%s [y|n] " % question)
        if choice == "y":
            answer = True
            break
        elif choice == "n":
            answer = False
            break
        else:
            print "Invalid input."
            
    return answer