diff --git a/docs/api-guide/validators.md b/docs/api-guide/validators.md
index bb8466a2c..d48d1df7b 100644
--- a/docs/api-guide/validators.md
+++ b/docs/api-guide/validators.md
@@ -271,6 +271,7 @@ A validator may be any callable that raises a `serializers.ValidationError` on f
     def even_number(value):
         if value % 2 != 0:
             raise serializers.ValidationError('This field must be an even number.')
+        return value
 
 #### Field-level validation