Error: The removeAllSummerPeople() method not working

I can't find the problem. Can anyone help me with this one? public static void removeAllSummerPeople(HashMap<String, Date> map) { Iterator<HashMap.Entry<String, Date>> iterator = map.entrySet().iterator(); while (iterator.hasNext()){ Map.Entry<String, Date> pair = iterator.next(); Date birth = pair.getValue(); int month = birth.getMonth(); if (month == 6 || month == 7 || month ==8){ iterator.remove(); } //write your code here }}