Exercise $3$ Add an equals instance method to the IntList class, so that $x.$ equals $(y)$ returns true if the IntList $x$ and the IntList $y$ have exactly the same integers in the same order and returns false otherwise. It should be true that $x.$ equals $(y)$ is always equivalent to $y.$ equals $(x).$ It should also be true that if $x=my$ then $x,$ equals $(y),$ although the reverse should not necessarily be true.