I’ve never had the experience myself, but I would assume he means you would have to build in some type of retry logic in your script.
Just from a cursory glance, I couldn’t find any samples of how to do a multipart upload with retries in Python with Boto3.
This is an example of how to do multipart uploads though.
https://medium.com/@niyazi_erd/aws-s3-multipart-upload-with-...
Fun Trivia note: when you do a multipart upload, the S3 hash of the object is not the same as it is when you do a single part upload. I had a file with the same contents but a different hash when I used Python than when it was transferred with the CLI or CloudBerry. The quick and dirty way to fix the hash is to copy the file to itself with Boto3.