code: def register(
          app):
      
  
      # Pick a handler based on the requested format. Currently we assume the
      # caller wants JSON.
      error_handler = json.http_exception_error_handler
  
  
      @app.errorhandler(400)
      def handle_bad_request(
              exception):
          return error_handler(exception)
  
  
      @app.errorhandler(404)
      def handle_not_found(
              exception):
          return error_handler(exception)
  
  
      @app.errorhandler(405)
      def handle_method_not_allowed(
              exception):
          return error_handler(exception)
  
  
      @app.errorhandler(422)
      def handle_unprocessable_entity(
              exception):
          return error_handler(exception)
  
  
      @app.errorhandler(500)
      def handle_internal_server_error(
              exception):
          return error_handler(exception)
docs: Register all HTTP error code error handlers
  
      Currently, errors are handled by the JSON error handler.