Django REST Framework POST nested objects
<p>I'm facing a little problem right now with <em>Django Rest Framework</em>. I'm trying to post an object with nested objects in it.</p>

<p>Here are my <code>serializers.py</code>:</p>

<pre><code>class ClassSerializer(serializers.ModelSerializer):
    class Meta:
        model = Class
        fields = ('number', 'letter')


class SubjectSerializer(serializers.ModelSerializer):
    class Meta:
        model = Subject
        fields = ('title',)


class ExamSerializer(serializers.ModelSerializer):
    subject = SubjectSerializer()
    clazz = ClassSerializer()

    class Meta:
        model = Exam
        fields = ('id', 'subject', 'clazz', 'topic', 'date', 'details')
        depth = 1

    def create(self, validated_data):
        return Exam.objects.create(**validated_data)

    def update(self, instance, validated_data):
        instance.__dict__.update(**validated_data)
        instance.save()

        return instance
</code></pre>

<p>And <code>create()</code> from <code>views.py</code>:</p>

<pre><code>def create(self, request):
    serializer = self.serializer_class(data=request.data)
    serializer.is_valid(raise_exception=True)
    self.perform_create(serializer)

    return Response(serializer.validated_data, status=status.HTTP_201_CREATED)
</code></pre>

<p>And here it is the response from <em>Postman</em>:
<a href="https://i.stack.imgur.com/SIjVC.png" rel="noreferrer"><img src="https://i.stack.imgur.com/SIjVC.png" alt="Postman response"></a></p>

<p>I've read some posts here about this problem but I'm still stuck with it. I've tried to fix it in several ways but it is still returning <code>"This field is required."</code>.</p>