code: public NutMap pickAndRemoveBy(String regex) {
          if (Strings.isBlank(regex))
              return new NutMap();
          boolean isNot = regex.startsWith("!");
          Pattern p = Pattern.compile(isNot ? regex.substring(1) : regex);
          return pickAndRemoveBy(p, isNot);
      }
docs: 就是 pickAndRemoveBy 的一个便利写法
  
  @param regex
  正则表达式，! 开头表示取反
  @return 新 Map
  
  @see #pickAndRemoveBy(Pattern, boolean)