private List<ModificationItem> storeDiffs(
     AttributeFilter prev, AttributeFilter filter, List<ModificationItem> mods) {
   storeDiffTags(mods, "dcmTag", prev.getSelection(), filter.getSelection());
   storeDiff(
       mods, "dcmCustomAttribute1", prev.getCustomAttribute1(), filter.getCustomAttribute1());
   storeDiff(
       mods, "dcmCustomAttribute2", prev.getCustomAttribute2(), filter.getCustomAttribute2());
   storeDiff(
       mods, "dcmCustomAttribute3", prev.getCustomAttribute3(), filter.getCustomAttribute3());
   return mods;
 }
 private static Attributes storeTo(AttributeFilter filter, Entity entity, BasicAttributes attrs) {
   attrs.put("objectclass", "dcmAttributeFilter");
   attrs.put("dcmEntity", entity.name());
   attrs.put(tagsAttr("dcmTag", filter.getSelection()));
   storeNotNull(attrs, "dcmCustomAttribute1", filter.getCustomAttribute1());
   storeNotNull(attrs, "dcmCustomAttribute2", filter.getCustomAttribute2());
   storeNotNull(attrs, "dcmCustomAttribute3", filter.getCustomAttribute3());
   return attrs;
 }