code: public DeweyNumber increase(int times) {
  		int[] newDeweyNumber = Arrays.copyOf(deweyNumber, deweyNumber.length);
  		newDeweyNumber[deweyNumber.length - 1] += times;
  
  		return new DeweyNumber(newDeweyNumber);
  	}
docs: Creates a new dewey number from this such that its last digit is increased by the supplied
  number.
  
  @param times how many times to increase the Dewey number
  @return A new dewey number derived from this whose last digit is increased by given number