@Override
  public boolean contains(OIdentifiable identifiable) {
    if (newEntries.containsKey(identifiable)) return true;

    Change counter = changes.get(identifiable);

    if (counter != null) {
      AbsoluteChange absoluteValue = getAbsoluteValue(identifiable);

      if (counter.isUndefined()) {
        changes.put(identifiable, absoluteValue);
      }

      counter = absoluteValue;
    } else {
      counter = getAbsoluteValue(identifiable);
    }

    return counter.applyTo(0) > 0;
  }