text: class TestRouter(object):
  
      def db_for_read(self, model, **hints):
          """Read from diff_keys."""
          if model._meta.app_label == 'diff_keys':
              return 'diff_keys'
          return 'default'
  
      def db_for_write(self, model, **hints):
          """Write to diff_keys."""
          if model._meta.app_label == 'diff_keys':
              return 'diff_keys'
          return 'default'
  