def safe_dir(sub_dir=None):
    """Absolute path from safe package directory.

    :param sub_dir: Sub directory relative to safe package directory.
    :type sub_dir: str

    :return: The Absolute path.
    :rtype: str
    """
    safe_relative_path = os.path.join(
        os.path.dirname(__file__), '../')
    return os.path.abspath(
        os.path.join(safe_relative_path, sub_dir))