def post(self, request, pk, format=None):
     """Add a new message to thread."""
     thread = self.get_object(pk)
     serializer = MessageSerializer(data=request.data)
     if serializer.is_valid():
         self.create_message(serializer, thread)
         return Response(serializer.data, status=status.HTTP_201_CREATED)
     return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)
 def post(self, request, format=None):
     serializer = ThreadSerializer(data=request.data)
     if serializer.is_valid():
         self.perform_create(serializer)
         msg_serializer = MessageSerializer(data=dict(text=request.data['text'],
                                                      thread=serializer.data['id']))
         if msg_serializer.is_valid():
             msg_serializer.save(author=self.request.user)
         return Response(serializer.data, status=status.HTTP_201_CREATED)
     return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)