smart layer export return error

I was trying to find some usefull script and bumped into your gitHub

I noticed the smart layer export has some errors. Are you familiar with that?

<img width="532" alt="Screen Shot 2019-12-06 at 22 58 01" src="https://user-images.githubusercontent.com/6923008/70367959-ddd52980-187b-11ea-9948-04ca507a56b3.png">
