def no_going_back(confirmation):
    """Show a confirmation to a user.

    :param confirmation str: the string the user has to enter in order to
                             confirm their action.
    """
    if not confirmation:
        confirmation = 'yes'

    prompt = ('This action cannot be undone! Type "%s" or press Enter '
              'to abort' % confirmation)

    ans = click.prompt(prompt, default='', show_default=False)
    if ans.lower() == str(confirmation):
        return True

    return False
Show a confirmation to a user.

    :param confirmation str: the string the user has to enter in order to
                             confirm their action.