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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 in_system_path(filename):
 """ Return True if the file is in a system path """

    fn = sdk_normalize(os.path.realpath(filename))
    if fn.startswith('/usr/local/'):
        return False
    elif fn.startswith('/System/') or fn.startswith('/usr/'):
        return True
    else:
        return False