code: public static <T> Predicate<T> valuePresent() {
          return t -> t instanceof Value ? ((Value) t).toMaybe()
                                                      .isPresent()
                  : false;
      }
docs: <pre>
  {@code
  import static cyclops2.function.Predicates.valuePresent;
  
  Seq.of(Maybe.ofNullable(null),Maybe.just(1),null)
  .filter(valuePresent());
  
  //Seq[Maybe[1]]
  }
  </pre>
  @return A Predicate that checks if it's input is a cyclops2-react Value (which also contains a present value)