code: public String getDefaultParent(String entityTypeName) {
          SupportedEntityConfig entityConfig = entityTypeMap.get(entityTypeName);
          if (entityConfig != null) {
              return entityConfig.getDefaultParent();
          }
          return null;
      }
docs: Returns the default parent for the given prefixed entity type.
  Entity types under WIM package should not have any name space prefix. For example, "Person".
  
  @param entityTypeName The prefixed entity type.
  @return The unique name of the default parent of this entity type. If the entity type is not supported, null will be returned.