compare_to(old_snapshot: Snapshot, group_by: str, cumulative: bool=False)
Compute the differences with an old snapshot. Get statistics as a sorted list of StatisticDiff instances grouped by group_by.
See the Snapshot.statistics() method for group_by and cumulative parameters.
The result is sorted from the biggest to the smallest by: absolute value of StatisticDiff.size_diff, StatisticDiff.size, absolute value of StatisticDiff.count_diff, Statistic.count and then by StatisticDiff.traceback.