docs: def route(app_or_blueprint, context=default_context, **kwargs):
      """ attach a transmute route. """
      def decorator(fn):
          fn = describe(**kwargs)(fn)
          transmute_func = TransmuteFunction(fn)
          routes, handler = create_routes_and_handler(transmute_func, context)
          for r in routes:
              # push swagger info.
              if not hasattr(app_or_blueprint, SWAGGER_ATTR_NAME):
                  setattr(app_or_blueprint, SWAGGER_ATTR_NAME, SwaggerSpec())
              swagger_obj = getattr(app_or_blueprint, SWAGGER_ATTR_NAME)
              swagger_obj.add_func(transmute_func, context)
              app_or_blueprint.route(r, methods=transmute_func.methods)(handler)
          return handler
      return decorator