To access Amazon AWS S3 from Google App Engine, you not only need an S3
interface like simples3, but you'll also need a ported version of that
interface that works with Google's own urlfetch extension API.
gaes3 is exactly that, and is layered on top of simples3.
Usage is exactly like simples3, but with a different class:
>>> from gaes3 import AppEngineS3Bucket
>>> bucket = AppEngineS3Bucket("foo", access_key, secret_key)
>>> bucket.info("foo")["mimetype"]
'text/plain'