diff --git a/circle/vm/models/operation.py b/circle/vm/models/operation.py
index c9949aa..4398901 100644
--- a/circle/vm/models/operation.py
+++ b/circle/vm/models/operation.py
@@ -60,7 +60,7 @@ class Operation:
 
         Deriving classes should implement this method.
         """
-        pass
+        raise NotImplementedError
 
     def async(self, **kwargs):
         """Execute the operation asynchronously.