@Override
  public void put(@NotNull Integer key, @Nullable ByteArraySequence value) throws IOException {
    if (value == null) {
      myPersistentMap.remove(key);
    }
    else {
      myPersistentMap.put(key, value);
    }
  }
@Override
  public void put(@NotNull Integer key, @Nullable ByteArraySequence value)