# Based on https://stackoverflow.com/a/3041990
def query_yes_no(question, default="yes"):
    """Ask a yes/no question via input() and return their answer.

    "question" is a string that is presented to the user.
    "default" is the presumed answer if the user just hits <Enter>.
        It must be "yes" (the default), "no" or None (meaning
        an answer is required of the user).

    The "answer" return value is True for "yes" or False for "no".
    """
    valid = {"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("invalid default answer: '%s'" % default)
    while True:
        print(question + prompt, end='')
        choice = input().lower()
        if default is not None and choice == '': return valid[default]
        elif choice in valid: return valid[choice]
        else: print("Please respond with 'yes' or 'no' "
            "(or 'y' or 'n').\n")

# Based on https://stackoverflow.com/a/3041990
def query_yes_no(question, default='yes'):
    '''Ask a yes/no question via input() and return their answer.
    'question' is a string that is presented to the user.
    'default' is the presumed answer if the user just hits <Enter>.
        It must be 'yes' (the default), 'no' or None (meaning
        an answer is required of the user).
    The 'answer' return value is True for 'yes' or False for 'no'.
    '''
    valid = {'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('invalid default answer: "%s"' % default)
    while True:
        print(question + prompt, end='')
        choice = input().lower()
        if default is not None and choice == '': return valid[default]
        elif choice in valid: return valid[choice]
        else: print('Please respond with "yes" or "no" '
            '(or "y" or "n").\n')

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