I don't know where to point it out but pyvdp.org (Visa Development Portal Python Wrapper) is down. I have been using google cache to read it but if someone could look into this that would be helpful! Thanks!
I'm excited to learn that you're interested in Visa APIs. However, it looks like that's not a Visa website so you'll have to reach out to the appropriate person(s) that maintain that site. On the other hand, we do have a good amount of Visa API information here on our Visa Developer Center website. https://developer.visa.com/
Feel free to poke around our sandbox Code Explorer and API Explorer that's readily available for you to start testing code.
To access sandbox testing just navigate to the API documentation of your choice then follow the steps below to locate Sandbox Code Explorer.
Start Using Sandbox Code Explorer
In addition to that, we also have API Explorer. API Explorer lets you choose the Product API, Endpoint and Method to see the Request and Response. Link to API Explorer - https://developer.visa.com/apiexplorer
Enjoy exploring our Visa APIs and let us know if you need help or have questions!