Guidance manipulating files in S3 using Script (Python) snap

I would like to read a file from a S3 bucket, update the file, then write it back to S3. I would like to use the account in SnapLogic I configured for S3 use. Does anyone have an example of any of this they could share?

File Reader -> Stuff -> File Writer ?

Basically, yes. I would like to read a file from s3, manipulate it in some way, then write it back to s3.