Have you authenticated using this code snippet ? In the code snippet, replace placeholders for SH client id and SH client secret with your values. Running the snippet will define oauth session, which is then used in all our python examples and makes sure that requests have correct Authorization header.
The example looks ok. I have also run the code with my SH account and it works correctly.
The error message you got is really strange, since I can see you got the access token correctly (the last line in your image).
It could be that there was some glitch in the system. Could you please try again. If you are sill getting the same error, please send me a private message with the email (or user id) of your SH account with which you are making this requests.