diff --git a/IPython/html/services/notebooks/filenbmanager.py b/IPython/html/services/notebooks/filenbmanager.py
index d5728fa..4187249 100644
--- a/IPython/html/services/notebooks/filenbmanager.py
+++ b/IPython/html/services/notebooks/filenbmanager.py
@@ -26,7 +26,7 @@ from tornado import web
from .nbmanager import NotebookManager
from IPython.nbformat import current
-from IPython.utils.traitlets import Unicode, Dict, Bool, TraitError
+from IPython.utils.traitlets import Unicode, Bool, TraitError
from IPython.utils.py3compat import getcwd
from IPython.utils import tz
from IPython.html.utils import is_hidden, to_os_path
@@ -461,7 +461,7 @@ class FileNotebookManager(NotebookManager):
)
# ensure notebook is readable (never restore from an unreadable notebook)
with io.open(cp_path, 'r', encoding='utf-8') as f:
- nb = current.read(f, u'json')
+ current.read(f, u'json')
shutil.copy2(cp_path, nb_path)
self.log.debug("copying %s -> %s", cp_path, nb_path)