code: def _transform_snapshots_for_blockhash(storage: SQLiteStorage, cache: BlockHashCache) -> None:
      
  
      snapshots = storage.get_snapshots()
      snapshot_records = [
          TransformSnapshotRecord(
              data=snapshot.data,
              identifier=snapshot.identifier,
              storage=storage,
              cache=cache,
          )
          for snapshot in snapshots
      ]
  
      pool_generator = Pool(len(snapshots)).imap(_do_transform_snapshot, snapshot_records)
  
      updated_snapshots_data = []
      for result in pool_generator:
          updated_snapshots_data.append(result)
  
      storage.update_snapshots(updated_snapshots_data)
docs: Upgrades the snapshots by adding the blockhash to it and to any pending transactions