diff --git a/adafruit_ble_magic_light.py b/adafruit_ble_magic_light.py
index 2a2b964..a045d3d 100644
--- a/adafruit_ble_magic_light.py
+++ b/adafruit_ble_magic_light.py
@@ -63,7 +63,7 @@ def __setitem__(self, index: int, value: int) -> None:
         self._control = self._buf
         self._color = value
 
-    def __len__(self):
+    def __len__(self) -> int:
         return 1
 
     # Brightness doesn't preserve the color so comment it out for now. There are many other