1 files changed, 3 insertions, 3 deletions
diff --git a/docs/api-guide/serializers.md b/docs/api-guide/serializers.md
index e8d3c1b5..42edf9af 100644
--- a/docs/api-guide/serializers.md
+++ b/docs/api-guide/serializers.md
@@ -42,9 +42,9 @@ Declaring a serializer looks very similar to declaring a form:
             data will simply return a dictionary of items.
             """
             if instance is not None:
-                instance.title = attrs['title']
-                instance.content = attrs['content']
-                instance.created = attrs['created']
+                instance.title = attrs.get('title', instance.title)
+                instance.content = attrs.get('content', instance.content)
+                instance.created = attrs.get('created', instance.created)
                 return instance
             return Comment(**attrs)