Understanding DRF Serializers and Nested Relationships

from rest_framework import serializers
from django.db import models

class Author(models.Model):
    name = models.CharField(max_length=100)
    email = models.EmailField()

class Book(models.Model):
    title = models.CharField(max_length=200)
    author = models.ForeignKey(Author, on_delete=models.CASCADE, related_name='books')
    published_date = models.DateField()

class AuthorSerializer(serializers.ModelSerializer):
    books = serializers.SerializerMethodField()
    
    class Meta:
        model = Author
        fields = ['id', 'name', 'email', 'books']
    
    def get_books(self, obj):
        books = obj.books.all()
        return BookSerializer(books, many=True).data

class BookSerializer(serializers.ModelSerializer):
    class Meta:
        model = Book
        fields = ['id', 'title', 'author', 'published_date']