old_contents: from django.db import models
  
  
  class Country(models.Model):
      name = models.CharField(max_length=50)
      country_code = models.CharField(max_length=5)
  
  
  class Author(models.Model):
      first_name = models.CharField(max_length=50)
      middle_name = models.CharField(max_length=20)
      last_name = models.CharField(max_length=100)
      date_of_birth = models.DateField('Date of birth')
      birthplace = models.CharField(max_length=100)
      country = models.ForeignKey(Country)
  
  
  class Book(models.Model):
      author = models.ForeignKey(Author)
      title = models.CharField(max_length=200)
      pub_date = models.DateField('Publication date')
  
new_contents: from django.db import models
  
  class Country(models.Model):
      name = models.CharField(max_length=50)
      country_code = models.CharField(max_length=5)
  
  
  class Status(models.Model):
      name = models.CharField(max_length=10)
  
  
  class Author(models.Model):
      first_name = models.CharField(max_length=50)
      middle_name = models.CharField(max_length=20)
      last_name = models.CharField(max_length=100)
      date_of_birth = models.DateField('Date of birth')
      birthplace = models.CharField(max_length=100)
      country = models.ForeignKey(Country)
  
  
  class Book(models.Model):
      author = models.ForeignKey(Author)
      title = models.CharField(max_length=200)
      pub_date = models.DateField('Publication date')
  
subject: add status model