You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: Solution.go
    path of file: ./repos/awesome-golang-algorithm/leetcode/1701-1800/1721.Swapping-Nodes-in-a-Linked-List
    
    the code of the file until where you have to start completion: package Solution

type ListNode struct {
	Val  int
	Next *ListNode
}

func Solution(head *ListNode, k int) *ListNod
    
func Solution1(head *ListNode, k int) *ListNode {
	walker := head
	for i := 1; i < k; i++ {
		walker = walker.Next
	}
	one := walker
	two := head
	for ; walker.Next != nil; walker = walker.Next {
		two = two.Next
	}
	one.Val, two.Val = two.Val, one.Val
	return head
}