docs: public static String extractMultiAndDelPre(Pattern pattern, Holder<CharSequence> contentHolder, String template) {
  		if (null == contentHolder || null == pattern || null == template) {
  			return null;
  		}
  
  		HashSet<String> varNums = findAll(PatternPool.GROUP_VAR, template, 1, new HashSet<String>());
  
  		final CharSequence content = contentHolder.get();
  		Matcher matcher = pattern.matcher(content);
  		if (matcher.find()) {
  			for (String var : varNums) {
  				int group = Integer.parseInt(var);
  				template = template.replace("$" + var, matcher.group(group));
  			}
  			contentHolder.set(StrUtil.sub(content, matcher.end(), content.length()));
  			return template;
  		}
  		return null;
  	}