old_contents: DATABASES = {
      'default': {
          'ENGINE': 'django.db.backends.sqlite3',
          'NAME': ':memory:',
      },
  }
  
  INSTALLED_APPS = (
      'rest_framework_msgpack',
  )
  
new_contents: DATABASES = {
      'default': {
          'ENGINE': 'django.db.backends.sqlite3',
          'NAME': ':memory:',
      },
  }
  
  INSTALLED_APPS = (
      'rest_framework_msgpack',
  )
  
  SECRET_KEY = "Cr5Y6i7NSRq8sqp*1_HC_Owl6tt3S="
  
subject: add SECRET_KEY for testing