Fix deprecation warning in codeworld-api.
Fix deprecation warning in codeworld-api.

tgdavies/codeworld,alphalambda/codeworld,tgdavies/codeworld,alphalambda/codeworld,google/codeworld,alphalambda/codeworld,google/codeworld,pranjaltale16/codeworld,pranjaltale16/codeworld,pranjaltale16/codeworld,tgdavies/codeworld,google/codeworld