use request.setHeader

pandora_client/server.py

@@ -93,7 +93,7 @@ class Server(Resource):
         )
 
     def render_json(self, request, response):
-        request.headers['Content-Type'] = 'application/json'
+        request.setHeader('Content-Type', 'application/json')
         return json.dumps(response, indent=2)
 
     def getChild(self, name, request):
@@ -177,7 +177,7 @@ class Server(Resource):
                 'queue': queued,
                 'offline': offline
             })
-        request.headers['Content-Type'] = 'text/html'
+        request.setHeader('Content-Type', 'text/html')
         data = 'pandora_client distributed encoding server'
         return data