docs: @Override
      public void add(IBasicEntity entity) throws CachingException {
          final EntityIdentifier entityIdentifier = entity.getEntityIdentifier();
          final Class<? extends IBasicEntity> addType = entityIdentifier.getType();
  
          if (!this.entityType.isAssignableFrom(addType)) {
              throw new CachingException(
                      "Problem adding "
                              + entity
                              + ": entity type '"
                              + addType
                              + "' is incompatible with cache type '"
                              + this.entityType
                              + "'.");
          }
  
          this.cache.put(entityIdentifier.getKey(), entity);
      }