removed old code

// Next ...

func (fn *FibonacciNumber) Next() *big.Int {

	//r := f.current

	//n := big.NewInt(0)

	//n.Add(f.next, f.current)

	//f.current = f.next

	//f.next = n

	fn.current, fn.next = fn.next, fn.current.Add(fn.next, fn.current)

	return fn.current