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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 join_sys_path(currfile, dir_level_num=3):
 """ find certain path then load into sys path """

    if os.path.isdir(currfile):
        root_path = currfile
    else:
        root_path = get_base_dir(currfile, dir_level_num)

    sys.path.append(root_path)