code: def _has_fulltext(cls, uri):
  		
  		coll = cls._get_collection(uri)
  		with ExceptionTrap(storage.pymongo.errors.OperationFailure) as trap:
  			coll.create_index([('message', 'text')], background=True)
  		return not trap
docs: Enable full text search on the messages if possible and return True.
  		If the full text search cannot be enabled, then return False.