question_yes_no Function Python Snippet

question_yes_no.py

import sys

def question_yes_no(question, default="yes"):
    """Asks yes/no question using input() function and returns the answer

    Args:
        str: "question" text presented to user
        str: "default" the presumed answer if the user just hits <Enter>

    Returns:
        bool: "question_answer" is True for "yes" or False for "no"

    """
    valid_answer = {"yes": True, "y": True, "ye": True, "no": False, "n": False}
    if default is None:
        prompt = " [y/n] "
    elif default == "yes":
        prompt = " [Y/n] "
    elif default == "no":
        prompt = " [y/N] "
    else:
        raise ValueError("Opps! Invalid default answer: '%s'" % default)
    while True:
        sys.stdout.write(question + prompt)
        question_answer = input().lower()
        if default is not None and question_answer == '':
            return valid_answer[default]
        elif question_answer in valid_answer:
            return valid_answer[question_answer]
        else:
            sys.stdout.write("Opps! Please respond with 'yes' or 'no' (or 'y' or 'n')\n")