public class Monad<T> {
  private final T value;
  public Monad(T value) {
    this.value = value;
  }
  public <U> Monad<U> map(Function<T, U> mapperFunction) {
    return new Monad<>(mapping.apply(value));
  }
  public <U> Monad<U> flatMap(Function<T, Monad<U>> mapperFunction) {
    return mapperFunction.apply(value);
  }
}