code: @SuppressWarnings("unchecked")
          public <R> R forThose(RFunc2<Boolean, K, V> predicate, VFunc3<K, V, IteratorInfo<R>> func) {
                  return (R) forThose(predicate, Style.$(func));
          }
docs: define a function to deal with each element in the map
  
  @param predicate a function takes in each element from map and returns
  true or false(or null)
  @param func      a function takes in each element from map and iterator
  info
  @return return 'last loop value'.<br>
  check
  <a href="https://github.com/wkgcass/Style/">tutorial</a> for
  more info about 'last loop value'
  @see IteratorInfo