def extend_is_dir(value, minimum=None, maximum=None):
    u"""
    This function is extended is_dir().
    This function was able to take ListType or StringType as argument.
    """

    if isinstance(value, list):
        return [is_dir(member)
                for member in validate.is_list(value, minimum, maximum)]

    else:
        return is_dir(value)