diff --git a/seahub/notifications/views.py b/seahub/notifications/views.py
index 6351bb7471..2eddd4bcb1 100644
--- a/seahub/notifications/views.py
+++ b/seahub/notifications/views.py
@@ -1,5 +1,5 @@
-import datetime
 import simplejson as json
+from django.conf import settings
 from django.core.urlresolvers import reverse
 from django.contrib import messages
 from django.http import HttpResponseRedirect, Http404, HttpResponse
@@ -8,8 +8,6 @@ from django.template import RequestContext
 from django.template.loader import render_to_string
 from django.utils.translation import ugettext as _
 
-import seaserv
-
 from seahub.auth.decorators import login_required, login_required_ajax
 from seahub.notifications.models import Notification, NotificationForm, \
     UserNotification
diff --git a/seahub/views/ajax.py b/seahub/views/ajax.py
index 0a3401b69b..c40653131f 100644
--- a/seahub/views/ajax.py
+++ b/seahub/views/ajax.py
@@ -1341,6 +1341,9 @@ def set_notice_seen_by_id(request):
 
 @login_required_ajax
 def repo_remove(request, repo_id):
+    ct = 'application/json; charset=utf-8'
+    result = {}
+
     if get_system_default_repo_id() == repo_id:
         result['error'] = _(u'System library can not be deleted.')
         return HttpResponse(json.dumps(result), status=403, content_type=ct)