code: public static <T1, T2, T3> Func3<T1, T2, T3, Void> toFunc(final Action3<T1, T2, T3> action) {
          return toFunc(action, (Void) null);
      }
docs: Converts an {@link Action3} to a function that calls the action and returns {@code null}.
  
  @param action the {@link Action3} to convert
  @return a {@link Func3} that calls {@code action} and returns {@code null}