Fixed key error problem in csrf_inject

server.py

@@ -94,7 +94,7 @@ def csrf_protect(func):
 
 @app.url_defaults
 def csrf_inject(endpoint, values):
-	if endpoint not in csrf_endpoints or not session['_csrf_token']:
+	if endpoint not in csrf_endpoints or not session.get('_csrf_token'):
 		return
 	values['_csrf_token'] = session['_csrf_token']