diff --git a/monkey/monkey_island/cc/services/representations.py b/monkey/monkey_island/cc/services/representations.py
index a441a45b8..e21fcdb25 100644
--- a/monkey/monkey_island/cc/services/representations.py
+++ b/monkey/monkey_island/cc/services/representations.py
@@ -11,7 +11,7 @@ from common.utils import IJSONSerializable
 
 
 class APIEncoder(JSONEncoder):
-    def default(self, value: Any):
+    def default(self, value: Any) -> Any:
         # ObjectId is serializible by default, but returns a dict
         # So serialize it first into a plain string
         if isinstance(value, bson.objectid.ObjectId):