old_contents: 
  from django.conf import settings
  DB = list(settings.DATABASES)
  
  class PrivateAppRouter(object):
      """
      Allows an app to have it's own private database if needed
      """
      db_for_write = db_for_read
  
      def db_for_read(self, model, **hints):
          if model._meta.app_label in DB:
              return model._meta.app_label
  
      def allow_relation(self, obj1, obj2, **hints):
          if obj1._state.db == obj2._state.db:
              return True
          return None
  
      def allow_migrate(self, db, app_label, model_name=None, **hints):
          return app_label not in DB
  
  
new_contents: 
  from django.conf import settings
  DB = list(settings.DATABASES)
  
  class PrivateAppRouter(object):
      """
      Allows an app to have it's own private database if needed
      """
      def db_for_read(self, model, **hints):
          if model._meta.app_label in DB:
              return model._meta.app_label
      db_for_write = db_for_read
  
      def allow_relation(self, obj1, obj2, **hints):
          if obj1._state.db == obj2._state.db:
              return True
          return None
  
      def allow_migrate(self, db, app_label, model_name=None, **hints):
          return app_label not in DB
  
  
subject: Fix simple mistake