docs: public <T2, R1, R2> Unrestricted<R2> forEach3(Function<? super T, ? extends Unrestricted<R1>> value2,
                                                    BiFunction<? super T, ? super R1, ? extends Unrestricted<R2>> value3) {
  
          return this.flatMap(in -> {
  
              Unrestricted<R1> a = value2.apply(in);
              return a.flatMap(ina -> {
                  Unrestricted<R2> b = value3.apply(in,ina);
                  return b;
              });
  
  
          });
  
      }