Error when converting 00511440.h5 to .step file

[doralune]

util/export2step.py becomes error below for 00511440.h5, but fine for 00511440.json

AttributeError: 'NoneType' object has no attribute 'IsNull'

I recreated the h5 file by dataset/json2vec.py, ran util/export2step.py again and got the same error.
Something might have been different when converting from json to h5.

For 00511440.h5, the body in create_CAD() was None after the last step of ['NewBodyFeatureOperation', 'JoinFeatureOperation', 'NewBodyFeatureOperation', 'JoinFeatureOperation'].

https://github.com/ChrisWu1997/DeepCAD/blob/f7b350790a3bce0267a5345339fd09be0250c8cb/cadlib/visualize.py#L25-L37