I plan to use machine learning in Moodle.
Have any of you used Machine learning backends https://moodledev.io/docs/apis/plugintypes/mlbackend and can tell us about your experiences?
On the hosting I do not have access to Python. Is there a free Python available somewhere?
As an Admin user, check the settings for 'PATH'. Moodle does have a setting for python that is not enabled by default. The suggested path for python you see on that screen is a guess ... it's not a discovery. Most linux platforms do have python installed.
Setting that path and then saving, a green check will appear beside python setting indicates moodle was able to find python.
While you are there, might also set the path to php-cli as that will allow a 'run now' link to show in scheduled task (part of cron job) which, if having issues with some areas of your site, might come in handy! 
'SoS', Ken