Warning: there is no registered PB decoder for Sentiment

[konishon]

I followed discussion on https://github.com/src-d/hercules/issues/300 and ran ./hercules --feature uast --languages java --sentiment --pb https://github.com/fieldsight/fieldsight-mobile | labours -m sentiment -f pb

However, I get Warning: there is no registered PB decoder for Sentiment done Running: sentiment Sentiment stats were not collected. Re-run hercules with --sentiment.