@Contract(pure = true)
  private static @Nullable String mapToFlatMap(String mapMethod) {
    return switch (mapMethod) {
      case "map" -> "flatMap";
      case "mapToInt" -> "flatMapToInt";
      case "mapToLong" -> "flatMapToLong";
      case "mapToDouble" -> "flatMapToDouble";
      default ->
        // Something unsupported passed: ignore
        null;
    };
  }
@Contract(pure = true)
  private static @Nullable String mapToFlatMap(String mapMethod)