Django Rest Framework更新嵌套的m2m对象。有谁知道更好的方法？

Question

我有一个案例，用户需要更新一个instance以及在此实例上添加/编辑m2m相关对象。

这是我的解决方案：

# models.py

class AdditionalAction(SoftDeletionModel):
    ADDITIONAL_CHOICES = (
        ('to_bring', 'To bring'),
        ('to_prepare', 'To prepare'),
    )
    title = models.CharField(max_length=50)
    type = models.CharField(choices=ADDITIONAL_CHOICES, max_length=30)

class Event(models.Model):
     title= models.CharField(max_length=255)
     actions = models.ManyToManyField(AdditionalAction, blank=True)



# serializers.py
class MySerializer(serializers.ModelSerializer):
    def update(self, instance, validated_data):
        actions_data = validated_data.pop('actions')

        # Use atomic block to rollback if anything raised Exception 
        with transaction.atomic():

            # update main object
            updated_instance = super().update(instance, validated_data)

            actions = []
            # Loop over m2m relation data and
            # create/update each action instance based on id present
            for action_data in actions_data:
                action_kwargs = {
                    'data': action_data
                }
                id = action_data.get('id', False)
                if id:
                    action_kwargs['instance'] = AdditionalAction.objects.get(id=id)
                actions_ser = ActionSerializerWrite(**action_kwargs)
                actions_ser.is_valid(raise_exception=True)
                actions.append(actions_ser.save())

            updated_instance.actions.set(actions)

        return updated_instance

谁能建议更好的解决方案？

附：在这种情况下可以创建或更新动作，所以我不能在序列化器上使用many=True，因为它还需要instance来更新。