def is_module_stdlib(file_name):
    """Returns True if the file_name is in the lib directory."""
    # TODO: Move these calls away from this function so it doesn't have to run
    # every time.
    lib_path = sysconfig.get_python_lib()
    path = os.path.split(lib_path)
    if path[1] == 'site-packages':
        lib_path = path[0]
    return file_name.lower().startswith(lib_path.lower())