The code as it stands is of course really dumb, but I think you can just pass `None` to each of those and have boto3 use the standard credential precedence. On

The code as it stands is of course really dumb, but I think you can just pass `None` to each of those and have boto3 use the standard credential precedence. On top of that they have mutable keyword arguments and generally quite terrible code: no exceptions thrown, just logging.error(), `if len(x)` rather than `if x`, etc etc.