Flat serializer for Django-rest-framework

serializers.py

class UserProfileSerializer(serializer.ModelSerializer):
    class Meta:
        model = UserProfile
        fields = ['profile_info']


class UserSerializer(serializer.ModelSerializer):
    profile_info = serializers.CharField(source='profile.profile_info')
    class Meta:
        model = User
        fields = ['email', 'username']

viewset.py

"""
GET method does not need both serializers just the main one.
For  POST, PATCH and PUT we need to initialize both serializer with the request data
and make all verification with both.

This code is not complete. When both objects are created(user and profile) they are not
related yet and maybe this will raise an exception (if profile.user can not be null).
"""
class CreateModelMixin(object):
    def create(self, request, *args, **kwargs):
        user_serializer = UserSerializer(data=request.DATA, files=request.FILES)
        profile_serializer = UserProfileSerializer(data=request.DATA, files=request.FILES)

        if user_serializer.is_valid() and profile_serializer.is_valid():
            self.pre_save(user_serializer.object)
            self.object = user_serializer.save(force_insert=True)
            profile_serializer.save()
            self.post_save(self.object, created=True)
            headers = self.get_success_headers(serializer.data)
            return Response(serializer.data, status=status.HTTP_201_CREATED,
                            headers=headers)
        serializers_errors = user_serializer.errors.copy()
        serializers_errors.update(user_profile_serializer.errors)
        return Response(serializers_errors, status=status.HTTP_400_BAD_REQUEST)