diff --git a/rest_framework/utils/serializer_helpers.py b/rest_framework/utils/serializer_helpers.py
index b9b2f8c67..1b3f8ea93 100644
--- a/rest_framework/utils/serializer_helpers.py
+++ b/rest_framework/utils/serializer_helpers.py
@@ -116,4 +116,4 @@ class BindingDict(object):
             return default
 
     def __len__(self):
-        return len(self.fields())
+        return len(self.fields())
\ No newline at end of file