How to work with drf-extension (Django Rest Framework) if the model has lookup_fields assigned

Question

It would be better if I give an example that I was working on. The Models are

class Author(models.Model):
    id = models.IntegerField(db_column='a_id', primary_key=True)
    first_name = models.CharField(max_length=20)
    last_name = models.CharField(max_length=20)

class Book(models.Model):
    id = models.IntegerField(db_column='b_id', primary_key=True)
    title = models.CharField(max_length=60)
    author = models.ForeignKey(Author, on_delete=models.CASCADE)

And the Serializers are,

class AuthorSerializer(ModelSerializer):
    class Meta:
        model = Author
        fields = ('id', 'first_name', 'last_name')


class BookSerializer(ModelSerializer):
    class Meta:
        model = Book
        fields = ('id', 'author', 'title')

And the view sets are,

class AuthorViewSet(NestedViewSetMixin, ModelViewSet):
    serializer_class = AuthorSerializer
    queryset = Author.objects.all()


class BookViewSet(NestedViewSetMixin, ModelViewSet):
    serializer_class = BookSerializer
    queryset = Book.objects.all()

Now The following APIs are working okay,

/authors/
/authors/{author_id}/
/authors/{author_id}/books/

However, If I change the Author Views to

class AuthorViewSet(NestedViewSetMixin, ModelViewSet):
    serializer_class = AuthorSerializer
    queryset = Author.objects.all()
    lookup_field = 'first_name'

Then, the following APIs work

/authors/
/authors/{author_first_name}/

But the following doesn't work.

/authors/{author_first_name}/books/

I understand that it's because of the Foreign key relations between these two tables. I was just wondering whether there is any workaround if I want to keep the lookup_fields.

Thanks