Briefly explain what the following code does with an emphasis on the underlined parts. public static OrderedPair addPairs ( OrderedPair extends Number > pairl, OrderedPair extends Number pair2) Number newFirst = pair1.getFirst (). doubleValue () + pair2.getFirst ().doubleValue (); Number newsecond = pair1.getSecond () . doubleValue () + pair2.getFirst ().doubleValue () ; return new OrderedPair ((T) newFirst, (T) newSecond)