diff --git a/src/schnetpack_gschnet/data/datamodule.py b/src/schnetpack_gschnet/data/datamodule.py
index a391446..540284b 100644
--- a/src/schnetpack_gschnet/data/datamodule.py
+++ b/src/schnetpack_gschnet/data/datamodule.py
@@ -407,7 +407,7 @@ def load_partitions(self):
                 )
 
     def register_properties(self, properties: List[str]):
-        if properties is not None and len(properties) > 0:
+        if properties is not None:
             available_properties = self.dataset.available_properties
             for p in properties:
                 if p not in available_properties:
diff --git a/src/schnetpack_gschnet/model.py b/src/schnetpack_gschnet/model.py
index 56f7147..b1d1912 100644
--- a/src/schnetpack_gschnet/model.py
+++ b/src/schnetpack_gschnet/model.py
@@ -304,7 +304,7 @@ def predict_distances(
 
     def get_required_data_properties(self):
         if self.conditioning_module is None:
-            return None
+            return []
         else:
             return self.conditioning_module.required_data_properties