diff --git a/typedpkg/sample.py b/typedpkg/sample.py
index 0e9ea07..032fd1c 100644
--- a/typedpkg/sample.py
+++ b/typedpkg/sample.py
@@ -1,2 +1,2 @@
-def ex(a: int, b: str):
-    return b + f'{a}'
\ No newline at end of file
+def ex(a: int, b: str) -> str:
+    return b + f'{a}'