private @NotNull List<File> getExistentFiles(ClientLibraryDescription description) {
    List<File> files = myFiles.get(description.getId());
    if (files == null) {
      return Collections.emptyList();
    }
    List<File> existentFiles = new ArrayList<>();
    for (File file : files) {
      if (file.exists()) {
        existentFiles.add(file);
      }
    }
    return existentFiles;
  }
private @NotNull List<File> getExistentFiles(ClientLibraryDescription description)