code: public void deleteByKey(DatastoreKey key) {
      try {
        nativeWriter.delete(key.nativeKey());
      } catch (DatastoreException exp) {
        throw DatastoreUtils.wrap(exp);
      }
    }
docs: Deletes an entity given its key.
  
  @param key
  the entity's key
  @throws EntityManagerException
  if any error occurs while deleting.