We have started automatically blocking all requests that have the user agent python-requests/2.13.0 on our fleet of servers. This is because we have seen an increase of this user agents performing a malicious amount of requests, as can be seen in this graph:
If you do not want to have this user agent blocked, you can make the /data/web/nginx/server.malicious_python_requests empty.
We will be rolling out this change over the course of the coming week.