diff --git a/src/sdr/_helper.py b/src/sdr/_helper.py
index 95901ae7c..319aac17e 100644
--- a/src/sdr/_helper.py
+++ b/src/sdr/_helper.py
@@ -2,6 +2,8 @@
 A module containing various helper functions for the library.
 """
 
+from __future__ import annotations
+
 import builtins
 import inspect
 import sys
diff --git a/src/sdr/_nco.py b/src/sdr/_nco.py
index 27abc455b..6dda1881c 100644
--- a/src/sdr/_nco.py
+++ b/src/sdr/_nco.py
@@ -2,7 +2,7 @@
 A module for numerically controlled oscillators (NCO).
 """
 
-# from __future__ import annotations
+from __future__ import annotations
 
 from typing import Any, overload