diff --git a/notebook/serverextensions.py b/notebook/serverextensions.py
index adf394de9..c1e73de5e 100644
--- a/notebook/serverextensions.py
+++ b/notebook/serverextensions.py
@@ -17,7 +17,7 @@ from .nbextensions import (
 )
 
 from traitlets import Bool
-from traitlets.config.manager import BaseJSONConfigManager, recursive_update
+from traitlets.config.manager import BaseJSONConfigManager
 
 # ------------------------------------------------------------------------------
 # Public API
diff --git a/notebook/services/config/manager.py b/notebook/services/config/manager.py
index 1a1de6a40..b0b38b3f1 100644
--- a/notebook/services/config/manager.py
+++ b/notebook/services/config/manager.py
@@ -26,11 +26,11 @@ class ConfigManager(LoggingConfigurable):
             
     def set(self, section_name, data):
         """Set the config only to the user's config."""
-        self._write_config_manager.set(section_name, data)
+        self.write_config_manager.set(section_name, data)
 
     def update(self, section_name, new_data):
         """Update the config only to the user's config."""
-        self._write_config_manager.update(section_name, new_data)
+        self.write_config_manager.update(section_name, new_data)
 
     # Private API