avisdk

Create a comprehensive mini-application using the 'avisdk' Python package that allows users to manage their Avi Controller services more efficiently. Your application should enable users to perform the following actions:

1. List all virtual services deployed on the Avi Controller.
2. Create a new virtual service with specified parameters such as name, IP address, and port number.
3. Modify an existing virtual service's configuration (e.g., changing its IP address or port).
4. Delete a virtual service from the Avi Controller.
5. Retrieve detailed information about a specific virtual service.
6. Enable or disable a virtual service based on user input.

The application should provide a simple command-line interface where users can select options from a menu to execute these actions. Each action should validate inputs to ensure they are correct and provide appropriate error messages if something goes wrong.

Additionally, include a feature to save and load configurations from a local file for easy management of changes without needing to interact with the Avi Controller directly every time.

Use the 'avisdk' package's core functionalities to interact with the Avi Controller's REST API. This includes using its classes and methods to authenticate with the controller, retrieve information, and send commands to modify services. Ensure your code is well-documented and follows best practices for Python development.