ClusterTopology now requires the extract_group argument. This is because it was effectively required by the fact that it's called without checking for None. And all non-test usages set it.
GeneticBalancer.rebalance had a logic error where it tries to iterate over a dict. This works but just iterates over the keys of the dict, not the items. I fixed this by calling .items() on the dict and iterating over that. This implies that this code is dead though, since it almost certainly crashed and definitely didn't work.
A few notable things here:
extract_groupargument. This is because it was effectively required by the fact that it's called without checking forNone. And all non-test usages set it..items()on the dict and iterating over that. This implies that this code is dead though, since it almost certainly crashed and definitely didn't work.