RoBERTa - Creating a feature of type ClassLabel

Hi, I want to use roberta model and I’m trying to create a dataset whose ner_tags feature is of type ClassLabel, but casting is not possible when tags are nested inside a list. I get the error:

ArrowTypeError: (“Expected bytes, got a ‘list’ object”, ‘Conversion failed for column tokens with type object’)

And actually is the error mentioned here: How do I set feature type when loading dataset(ClassLabel etc)? - #2 by mariosasko

But datasets in Huggingface Datasets library do contain the feature ner_tags consisting of lists of tags, and are actually of ClassLabel type.

Is there any way to achieve this? Thanks a lot xx