code: @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
      public static <T, U> T iff(Optional<U> optional, Function<U, T> ifFunction) {
          if (Objects.nonNull(optional) && optional.isPresent()) {
              return optional.map(ifFunction).orElse(null);
          }
          return null;
      }
docs: Generic if-expression to if'ing inside method calls
  
  @param optional   The item that may be present
  @param ifFunction The function that will be called if that optional is present
  @param <T>        The derived generic parameter type
  @param <U>        The supplying generic parameter type
  @return transformed value if condition is true, null otherwise