+ # write_copies diverges from args.replication here.
+ # args.replication is how many copies we will instruct Arvados to
+ # maintain (by passing it in collections().create()) after all
+ # data is written -- and if None was given, we'll use None there.
+ # Meanwhile, write_copies is how many copies of each data block we
+ # write to Keep, which has to be a number.
+ #
+ # If we simply changed args.replication from None to a default
+ # here, we'd end up erroneously passing the default replication
+ # level (instead of None) to collections().create().
+ write_copies = (args.replication or
+ api_client._rootDesc.get('defaultCollectionReplication', 2))
+