Instantiation: The first image defines the class hierarchy as Native.Interface.FastEthernet. To configure a FastEthernet interface, you must instantiate this specific class from the imported model.

Configuration: The image shows the keepalive leaf has a type of bool. To "enable" it as requested, the attribute must be set to True. The attribute name is already set to '2/0' in the code to identify the specific interface.

Operation: To apply changes to the network device, the crud.update() method is used. This method sends the configuration to the device via the NETCONF provider. The resulting interface_data (often a boolean success indicator in YDK CRUD service) is then evaluated in the if statement to confirm the operation.

Official Vendor Documentation: Cisco Systems, Inc. "YDK-Py Documentation: Developer Guide - CRUD Service." This document specifies the use of crud.update(provider, entity) to modify existing configuration data on a device.

Official Vendor Documentation: Cisco Systems, Inc. "Cisco IOS XE YANG Data Models." This confirms the hierarchy where native contains interface, which in turn contains specific interface types like FastEthernet.

Official Vendor Documentation: Cisco DevNet. "Getting Started with YDK." Section: "How to use the CRUD Service," illustrating the workflow: Instantiate Object -> Set Values -> Call crud.update.

GitHub Repository (Official): CiscoDevNet/ydk-py. Models subdirectory for cisco-ios-xe, specifically the Cisco-IOS-XE-native.yang mapping which defines keepalive as a boolean leaf within the interface container.