4. Write a method, getMiddle Chars, the method receives a String and returns a String containing the middle character (as a String) or the middle 2 characters(as a String) found in the received String. If an empty String is received, returns an empty String. method signature: public static String getMiddleChars(String aString) Example values: getMiddleChars("hello") should return "1" getMiddleChars("hi") should return "hi" getMiddleChars("") should return getMiddleChars("K") should return "K" getMiddleChars("I Love CS") should return "v" getMiddleChars("Silly String work") should return