code: def require_request_model(cls, validate=True):
      
      def decorator(handler):
          async def new_handler(request, *args, **kwargs):
              body = await request.json()
              model = cls(**body)
  
              if validate:
                  model.validate()
  
              return await handler(request, model, *args, **kwargs)
          return new_handler
      return decorator
docs: Makes a handler require that a request body that map towards the given
      model is provided. Unless the ``validate`` option is set to ``False`` the
      data will be validated against the model's fields.
  
      The model will be passed to the handler as the last positional argument. ::
  
          @require_request_model(Model)
          async def handle_model(request, model):
              return 200, model