diff --git a/IPython/html/services/sessions/handlers.py b/IPython/html/services/sessions/handlers.py
index b194ca6..6d31f61 100644
--- a/IPython/html/services/sessions/handlers.py
+++ b/IPython/html/services/sessions/handlers.py
@@ -83,11 +83,9 @@ class SessionHandler(IPythonHandler):
     def patch(self, session_id):
         # Currently, this handler is strictly for renaming notebooks
         sm = self.session_manager
-        nbm = self.notebook_manager
-        km = self.kernel_manager
         model = self.get_json_body()
         if model is None:
-            raise HTTPError(400, "No JSON data provided")
+            raise web.HTTPError(400, "No JSON data provided")
         changes = {}
         if 'notebook' in model:
             notebook = model['notebook']
@@ -104,7 +102,6 @@ class SessionHandler(IPythonHandler):
     def delete(self, session_id):
         # Deletes the session with given session_id
         sm = self.session_manager
-        nbm = self.notebook_manager
         km = self.kernel_manager
         session = sm.get_session(id=session_id)
         sm.delete_session(session_id)        
diff --git a/IPython/html/services/sessions/sessionmanager.py b/IPython/html/services/sessions/sessionmanager.py
index ffec398..193ccc1 100644
--- a/IPython/html/services/sessions/sessionmanager.py
+++ b/IPython/html/services/sessions/sessionmanager.py
@@ -16,15 +16,13 @@ Authors:
 # Imports
 #-----------------------------------------------------------------------------
 
-import os
 import uuid
 import sqlite3
 
 from tornado import web
 
 from IPython.config.configurable import LoggingConfigurable
-from IPython.nbformat import current
-from IPython.utils.traitlets import List, Dict, Unicode, TraitError
+from IPython.utils.traitlets import TraitError
 
 #-----------------------------------------------------------------------------
 # Classes
diff --git a/IPython/html/services/sessions/tests/test_sessions_api.py b/IPython/html/services/sessions/tests/test_sessions_api.py
index 1c53d86..743789e 100644
--- a/IPython/html/services/sessions/tests/test_sessions_api.py
+++ b/IPython/html/services/sessions/tests/test_sessions_api.py
@@ -8,7 +8,6 @@ import shutil
 
 pjoin = os.path.join
 
-from IPython.utils.jsonutil import date_default
 from IPython.html.utils import url_path_join
 from IPython.html.tests.launchnotebook import NotebookTestBase
 from IPython.nbformat.current import new_notebook, write