diff --git a/modules/source/11_training/training_dev.py b/modules/source/11_training/training_dev.py
index 38b6b4a3..14f84872 100644
--- a/modules/source/11_training/training_dev.py
+++ b/modules/source/11_training/training_dev.py
@@ -200,6 +200,11 @@ class MeanSquaredError:
         """Alternative interface for forward pass."""
         return self.__call__(y_pred, y_true)
 
+# %% [markdown]
+"""
+## 🔧 DEVELOPMENT
+"""
+
 # %% [markdown]
 """
 ### 🧪 Unit Test: MSE Loss