diff --git a/src/gnn_tracking/utils/lightning.py b/src/gnn_tracking/utils/lightning.py
index fcf145f1..621aaa4d 100644
--- a/src/gnn_tracking/utils/lightning.py
+++ b/src/gnn_tracking/utils/lightning.py
@@ -132,10 +132,10 @@ def get_model(
         freeze: Whether to freeze the model
     """
     if not chkpt_path:
-        return
+        return None
     lm = get_lightning_module(class_path, chkpt_path, freeze=freeze)
     if lm is None:
-        return
+        return None
     return lm.model
 
 
diff --git a/src/gnn_tracking/utils/timing.py b/src/gnn_tracking/utils/timing.py
index ec12c08e..883cdcc9 100644
--- a/src/gnn_tracking/utils/timing.py
+++ b/src/gnn_tracking/utils/timing.py
@@ -29,4 +29,4 @@ def timing(name="Codeblock", logger=None):
     try:
         yield
     finally:
-        logger.info(f"{name} took {t():.2f} seconds")
+        logger.info("%s took %f seconds", name, t())
diff --git a/tests/test_tcn_training.py b/tests/test_tcn_training.py
index aa99f463..27d88361 100644
--- a/tests/test_tcn_training.py
+++ b/tests/test_tcn_training.py
@@ -83,7 +83,7 @@ def __post_init__(self):
 
 
 @pytest.mark.parametrize("t", _test_train_test_cases)
-def test_train(tmp_path, built_graphs, t: TestTrainCase) -> None:
+def test_train(built_graphs, t: TestTrainCase) -> None:
     fix_seeds()
     _, graph_builder = built_graphs
     g = graph_builder.data_list[0]