diff --git a/docs/freqai-feature-engineering.md b/docs/freqai-feature-engineering.md
index 0fa47ba73..6b8636e28 100644
--- a/docs/freqai-feature-engineering.md
+++ b/docs/freqai-feature-engineering.md
@@ -124,6 +124,8 @@ It is advisable to start from the template `feature_engineering_*` functions in
             / dataframe["close"]
             - 1
             )
+        
+        return dataframe
 ```
 
 In the presented example, the user does not wish to pass the `bb_lowerband` as a feature to the model,