gistfile1.py

    def post(self, request, format=None):
        serializer = self.get_serializer(data=request.DATA, files=request.FILES)
        if serializer.is_valid():
            some_function_to_save(serializer.object)
            return Response(serializer.data, status=status.HTTP_201_CREATED)

        return Response(serializer.errors, status=status.HTTP_400_BAD_REQUEST)