Sky Yin

Thanks for the info. I've followed the list and fixed the final issue. You have to add that 'loss_attr' to the file in the site-package rather than to the one...

I'm using the latest version as for now github.com/dmitryikh/leaves v0.0.0-20200503205002-939b6fa631dd and it works with v3 LightGBM model fine.