Hi @kylehuang,
I'm sorry but I must disagree about the documentation. https://developer.kaltura.com has plenty of API documentation and even includes step by step code tutorials which you can find here: https://developer.kaltura.com/recipes, including one for working with metadata [https://developer.kaltura.com/recipes/metadata#]
Granted, the code samples are currently available for the PHP, Ruby, JS and NodeJS clients [not Python] and we do plan to support additional clients in the future but saying the documentation is sparse and incomplete sounds very harsh considering the content available.
That said, if there is anything specific you feel is missing, you're welcome to provide feedback and we'll do our best to add it.