diff --git a/src/caoscrawler/identifiable_adapters.py b/src/caoscrawler/identifiable_adapters.py
index 02bd6ac2b0fe242a1cecc1e0f1bf43ae892c216e..517bc97402375a09d9ea3fc48e93db0eb8a87a15 100644
--- a/src/caoscrawler/identifiable_adapters.py
+++ b/src/caoscrawler/identifiable_adapters.py
@@ -445,8 +445,8 @@ class IdentifiableAdapter(metaclass=ABCMeta):
             return False
 
         appropriate_types = []
-        appropriate_types.extend(get_children_of_rt(
-            register_identifiable.get_property("is_referenced_by").value))
+        for rt in register_identifiable.get_property("is_referenced_by").value:
+            appropriate_types.extend(get_children_of_rt(rt))
         appropriate_types = [el.lower() for el in appropriate_types]
         if "*" in appropriate_types:
             return True
diff --git a/src/caoscrawler/sync_node.py b/src/caoscrawler/sync_node.py
index f2fa000b7e94dee90fd37faabafaaa810e0bba7d..0dc674ad4f6ed4eca5ce82b6b4b12a07f920b593 100644
--- a/src/caoscrawler/sync_node.py
+++ b/src/caoscrawler/sync_node.py
@@ -47,7 +47,7 @@ class TempID(int):
     pass
 
 
-class SyncNode:
+class SyncNode(db.Entity):
     """represents the information of an Entity as it shall be created in LinkAhead
 
     The following information is taken from an db.Entity object during initialization or when the
@@ -69,7 +69,7 @@ class SyncNode:
 
     def __init__(
         self, entity: db.Entity, registered_identifiable: Optional[db.RecordType] = None
-    ) -> None:
+    ):
         # db.Entity properties
         self.id: Union[int, TempID, str] = entity.id
         self.role = entity.role