'module' object has no attribute 'DatasmithCADSceneElement'

I don’t have no idea why the below message is showing.

Cmd: py “datasmithasm.py”
LogPython: Error: Traceback (most recent call last):
LogPython: Error: File “datasmithasm.py”, line 13, in <module>
LogPython: Error: ds_scene_in_memory = unreal.DatasmithCADSceneElement.construct_datasmith_scene_from_file(file_to_import, “/GGame”)
LogPython: Error: AttributeError: ‘module’ object has no attribute ‘DatasmithCADSceneElement’

--------------------the source of python----------------------------
import unreal

file_to_import = “*************.SLDASM”

Construct the Datasmith Scene from a file on disk.

ds_scene_in_memory = unreal.DatasmithCADSceneElement.construct_datasmith_scene_from_file(file_to_import, “/GGame”)