code: public List<String> getAttributeIdentifiers(EntityType sourceEntityType) {
      Entity entityTypeEntity =
          dataService.findOne(
              ENTITY_TYPE_META_DATA,
              new QueryImpl<>().eq(EntityTypeMetadata.ID, sourceEntityType.getId()));
  
      if (entityTypeEntity == null)
        throw new MolgenisDataAccessException(
            "Could not find EntityTypeEntity by the name of " + sourceEntityType.getId());
  
      List<String> attributeIdentifiers = new ArrayList<>();
  
      recursivelyCollectAttributeIdentifiers(
          entityTypeEntity.getEntities(EntityTypeMetadata.ATTRIBUTES), attributeIdentifiers);
  
      return attributeIdentifiers;
    }
docs: A helper function that gets identifiers of all the attributes from one EntityType