Prevent user from buying a course twice

Is there a way for me to prevent the user from buying (and thus enrolling) in a course twice?

For example, if a user is already enrolled in a course on Moodle, I would like the “Add to Cart” option to be disabled.

(If there are any simple code snippets that I can use to perform this check, I can look into that too.)

https://www.ads-software.com/plugins/moowoodle/