default @NotNull PrefixSuffix splitLabel() {
    String string = label();
    int splitPos = string.indexOf("|");
    return splitPos == -1 ? new PrefixSuffix(string, "") : new PrefixSuffix(string.substring(0, splitPos), string.substring(splitPos + 1));
  }
default @NotNull PrefixSuffix splitLabel()