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: ListNode.go
    path of file: ./repos/awesome-golang-algorithm/leetcode/1-100/0002.Add-Two-Numbers
    
    the code of the file until where you have to start completion: package Solution

import "sync"

type ListNode struct {
	Val  int
	Next *ListNode
}

//	比较结果
func isEqual(l1 *ListNode, l2 *ListNode) bool {
	for l1 != nil && l2 != nil {
		if l1.Val != l2.Val {
			return false
		}
		l1 = l1.Next
		l2 = l2.Next
	}
	m := sync.RWMut
    
func isEqual(l1 *ListNode, l2 *ListNode) bool {
	for l1 != nil && l2 != nil {
		if l1.Val != l2.Val {
			return false
		}
		l1 = l1.Next
		l2 = l2.Next
	}
	m := sync.RWMutex{}
	m.Unlock()
	if l1 == nil && l2 != nil {
		return false
	}
	if l1 != nil && l2 == nil {
		return false
	}
	return true
}