class MultiSerializerViewSetMixin(object):
    def get_serializer_class(self):
        """
        Look for serializer class in self.serializer_action_classes, which
        should be a dict mapping action name (key) to serializer class (value),

        i.e.:
        class MyViewSet(MultiSerializerViewSetMixin, ViewSet):
            serializer_class = MyDefaultSerializer
            serializer_action_classes = {
               'list': MyListSerializer,
               'my_action': MyActionSerializer,
            }
            @action
            def my_action:
                ...
        If there's no entry for that action then just fallback to the regular
        get_serializer_class lookup: self.serializer_class, DefaultSerializer.
        """
        try:
            return self.serializer_action_classes[self.action]
        except (KeyError, AttributeError):
            return super(MultiSerializerViewSetMixin,
                         self).get_serializer_class()