I'm using Django 2.1, DRF 3.7.7.  

I've some models and their relative (model) serializers: these models are nested, and so are the serializers.
Let me give an example:

```
# models.py
class City(models.Model):
    name = models.CharField(max_length=50)

class Person(models.Model):
    surname = models.CharField(max_length=30)
    birth_place = models.ForeignKey(City)

# serializers.py
class CitySerializer(serializers.ModelSerializer):
    class Meta:
        model = models.CitySerializer
        fields = "__all__"

class PersonSerializer(serializers.ModelSerializer):
    birth_place = CitySerializer()

    class Meta:
        model = models.Person
        fields = "__all__"

```

If I submit an AJAX request with a json like:  

`{'surname': 'smith', 'birth_place': 42}`  

I get back a `Bad Request` response, containing: `Invalid data. Expected a dictionary, but got int.`

If I submit a nested json like:  

`{'surname': 'smith', 'birth_place': {'id': 42, 'name': 'Toronto'}}`  

the relation is not converted, the id field is ignored and the rest is parsed to:  

`OrderedDict([('birth_place', OrderedDict([('name', 'Toronto')]))])`

The following is the post method I'm using on a class-based view:

```
def post(self, request):
    print("Original data:", request.data)
    serializer = self.serializer_class(data=request.data)
    if serializer.is_valid():
        self.data = serializer.validated_data
        print("Parsed data:", self.data)
        ...

```

I only need to get data from the endpoints connected to the serializers, **I don't need to write/save anything** through the REST interface, since the POST processing of the form is done by Django.

**TL;DR**: How should I correctly submit a JSON request to a nested serializer, without having to write handmade conversions? Did I commit errors in setting up the serializers?

**Edit**: I've discovered that by adding `id = serializers.IntegerField()` to the serializer parent class (e.g. City), the serializer parser now processes the id. At least now I'm able to perform actions in the backend with django.