content: from django.db import models
  
  
  class Book(models.Model):
      TYPES = ((1, "Hardcover"), (2, "Softcover"))
      title = models.CharField(max_length=255)
      date_published = models.DateField()
      type = models.IntegerField(choices=TYPES, default=1)
  
  
  class Author(models.Model):
      name = models.CharField(max_length=1024)
      books = models.ManyToManyField(Book)
  