Arvados

Reviewing 7b4d7fa

Would it be possible to tighten the try block like this?

        try:
            collection = arvados.CollectionReader(arvados.Keep.get(self.collection_locator))
        except Exception as detail:
            print("%s: error: %s" % (self.collection_locator,detail) )
        else:
            for s in collection.all_streams():
                …

That would help make it clearer which part we actually expect to fail. It might be trickier if all_streams could also fail, though.

That's my only comment, so whether you make that change or can't, I think you're good to merge.