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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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))