docs: private static void checkPreconditions(List<String> requiredSubStrings) {
  		if( requiredSubStrings == null ) {
  			throw new NullPointerException("requiredSubStrings List should not be null");
  		} else if( requiredSubStrings.isEmpty() ) {
  			throw new IllegalArgumentException("requiredSubStrings List should not be empty");
  		}
  	}