class ContactRelationSeria lizer ReprSerializerMixin serializers Model

class ContactRelationSerializer(ReprSerializerMixin, serializers.ModelSerializer):
    contact = ContactSerializer()

    def create(self, validated_data):
        contact_data = validated_data.pop('contact')
        contact_id = self.initial_data['contact'].get('id')

        if contact_id:
            # Contact relation is getting created for an existing contact. We allow to modify contact's fields
            # before creating contact relation.
            contact = Contact.objects.get(pk=contact_id)
            for attr, value in contact_data.items():
                setattr(contact, attr, value)
            contact.save()
        else:
            # New contact relation and contact are getting created.
            primary_organization = self.context['request'].primary_organization
            contact = Contact.objects.create(organization=primary_organization, **contact_data)

        return ContactRelation.objects.create(contact=contact, **validated_data)