docs: function _prepSnapshot() {
              var config = this.constructor.config,
                  copy = (config.snapshotSerializer || config.serializer).serialize(this);
  
              // we don't want to store our snapshots in the snapshots because that would make the rollback kind of funny
              // not to mention using more memory for each snapshot.
              delete copy.$$snapshots;
  
              return copy
          }