diff --git a/source/docs/operators/addition_assignment.rst b/source/docs/operators/addition_assignment.rst
index 9146999..d3c306c 100644
--- a/source/docs/operators/addition_assignment.rst
+++ b/source/docs/operators/addition_assignment.rst
@@ -25,7 +25,7 @@ Time Complexity
 
 Remarks
 =======
-Equivalent to A = A + B.
+Equivalent to A = A + B, if **__iadd__** method is not defined
 
 Example
 =======