diff --git a/ExampleApp/Main/__init__.py b/ExampleApp/Main/__init__.py
index e4fcb9b2cfea6485164ba6edd784b4c8d2dc135b..5ac0295f2cbf2325640162ca360ecca2d8c9c083 100644
--- a/ExampleApp/Main/__init__.py
+++ b/ExampleApp/Main/__init__.py
@@ -5,7 +5,8 @@ def home():
   return render_template('home.html')
 
 def change_lang():
-  session['language'] = request.args.get('lang')
+  if request.args.get('lang'):
+    session['language'] = request.args.get('lang')
   print('session language: {0}, request lang {1}'.format(
     session['language'], request.args.get('lang')) )
   return render_template('change_language.html')
\ No newline at end of file