docs: Map<SnapshotIdentifier, CdoSnapshot> calculate(List<CdoSnapshot> snapshots) {
          Map<SnapshotIdentifier, CdoSnapshot> previousSnapshots = new HashMap<>();
          populatePreviousSnapshotsWithSnapshots(previousSnapshots, snapshots);
          List<CdoSnapshot> missingPreviousSnapshots = getMissingPreviousSnapshots(snapshots, previousSnapshots);
          populatePreviousSnapshotsWithSnapshots(previousSnapshots, missingPreviousSnapshots);
          return previousSnapshots;
      }