def exist?(class_name, identifier, refresh = false)
      !valid_id(class_name, identifier, refresh).nil?
    end
def exist?(class_name, identifier, refresh = false)
      !valid_id(class_name, identifier, refresh).nil?
    end
Call the 'exist?' method on a JSS::APIObject subclass
 using this APIConnection. See {JSS::APIObject.exist?}

 @param class_name[String,Symbol] The name of a JSS::APIObject subclass
   see {JSS.api_object_class}

 @param identifier[String,Symbol] the value to which the ids should be mapped

 @param refresh[Boolean] Should the data be re-read from the API?

 @return [Boolean] Is there an object of this class in the JSS matching
   this indentifier?