Are you using the latest version of the Python SDK? I tested the example for UsersApi.get_users(...) shown in the docs and it works fine using the latest Python SDK (v43.0.0). Can you try using the example there as its written? There are a few differences from the code you wrote.
The API functions use **kwargs, which require keyworded arguments. If that doesn't work, please post your latest code.
Edit: forgo to mention, if you're also having issues with the JavaScript SDK, please create a new topic with your issue in the JavaScript SDK category.
You specified an ID filter with no values. Getting a 404 not found from that request is normal. Try not providing the ID filter if you aren't wanting to retrieve specific users by ID.