diff --git a/src/mlstmyfasta/engine/data/genomics.py b/src/mlstmyfasta/engine/data/genomics.py
index e24698a..54e5906 100644
--- a/src/mlstmyfasta/engine/data/genomics.py
+++ b/src/mlstmyfasta/engine/data/genomics.py
@@ -15,5 +15,5 @@ class Strand:
     coding: str
     features: Sequence[StrandFeature]
 
-def get_feature_coding(strand: Strand, feature: StrandFeature):
-    strand.coding[feature.start:feature.end]
\ No newline at end of file
+def get_feature_coding(strand: Strand, feature: StrandFeature) -> str:
+    return strand.coding[feature.start:feature.end]
\ No newline at end of file