decode method 
    
    
    
  Implementation
  void decode(KeyedArchive object) {
  super.decode(object);
  tags = object.decode("tags");
  summary = object.decode("summary");
  description = object.decode("description");
  id = object.decode("operationId");
  parameters =
      object.decodeObjects("parameters", () => new APIParameter.empty());
  requestBody =
      object.decodeObject("requestBody", () => new APIRequestBody.empty());
  responses =
      object.decodeObjectMap("responses", () => new APIResponse.empty())
          as Map<String, APIResponse>?;
  callbacks = object.decodeObjectMap("callbacks", () => new APICallback())
      as Map<String, APICallback>?;
  _deprecated = object.decode("deprecated");
  security = object.decodeObjects(
      "security", () => new APISecurityRequirement.empty());
  servers =
      object.decodeObjects("servers", () => APIServerDescription.empty());
}