code: public final Promise clean(String match) {
  		ScanArgs args = new ScanArgs();
  		args.limit(100);
  		boolean singleStar = match.indexOf('*') > -1;
  		boolean doubleStar = match.contains("**");
  		if (doubleStar) {
  			args.match(match.replace("**", "*"));
  		} else if (singleStar) {
  			if (match.length() > 1 && match.indexOf('.') == -1) {
  				match += '*';
  			}
  			args.match(match);
  		} else {
  			args.match(match);
  		}
  		if (!singleStar || doubleStar) {
  			match = null;
  		}
  		if (client != null) {
  			return new Promise(clean(client.scan(args), args, match));
  		}
  		if (clusteredClient != null) {
  			return new Promise(clean(clusteredClient.scan(args), args, match));
  		}
  		return Promise.resolve();
  	}
docs: Deletes a group of items. Removes every key by a match string.
  
  @param match
  regex
  
  @return Promise with empty value