old_contents: 
  DATABASES = {
      'default': {
          'ENGINE': 'django.db.backends.sqlite3'
      },
  }
  
  INSTALLED_APPS = [
      'anonymizer',
      'anonymizer.tests',
  ]
  
new_contents: DATABASES = {
      'default': {
          'ENGINE': 'django.db.backends.sqlite3'
      },
  }
  
  INSTALLED_APPS = [
      'anonymizer',
      'anonymizer.tests',
  ]
  
  SECRET_KEY = 'foo bar baz'
  
subject: define required SECRET_KEY so tests can start