gistfile1.py

from django.db import models

class Author(models.Model):
    first_name = models.CharField(max_length=255)
    last_name = models.CharField(max_length=255)
    books = models.ManyToManyField('Book')

class Book(models.Model):
    title = models.CharField(max_length=255)

class BookStore(model.Model):
    name = models.CharField(max_length=255)
    books = models.ManyToManyField('Book')