diff --git a/src/caosdb/utils/plantuml.py b/src/caosdb/utils/plantuml.py
index 0c7936a98e27ec020659d9f7042cd05a9084ef4b..c226a2fe1850f2c95b0a0ccef230842e9644c5e5 100644
--- a/src/caosdb/utils/plantuml.py
+++ b/src/caosdb/utils/plantuml.py
@@ -111,6 +111,8 @@ def recordtypes_to_plantuml_string(iterable,
     - Inheritance of Properties is not rendered nicely at the moment.
     """
 
+    # TODO: This function needs a review of python type hints.
+
     classes = [el for el in iterable
                if isinstance(el, db.RecordType)]
     dependencies = {}