在groovy中将映射列表转换为嵌套映射

我有一份地图清单

b = [{key1=hello, key2=world}, {key1=hello2, key2=world2}, {key1=hello3, key2=world3}, {key1=hello4, key2=world4}]

我怎么把它转换成这样的东西

b = [{key1=hello, key2=world, {key1=hello2, key2=world2, {key1=hello3, key2=world3, {key1=hello4, key2=world4}}}}]

输出：

{
    "key1": "hello",
    "key2": "world",
    "next": {
        "key1": "hello2",
        "key2": "world2",
        "next": {
            "key1": "hello3",
            "key2": "world3",
            "next": null
        }
    }
}

---

你已经试过代码了吗？第二个b不是地图对不起，我是groovy新手。我还没有尝试任何东西。AddInjecteer说，b不是一个有效的映射，它介于映射和列表之间。。。你到底想要什么样的输出？

{
    "key1": "hello",
    "key2": "world",
    "next": {
        "key1": "hello2",
        "key2": "world2",
        "next": {
            "key1": "hello3",
            "key2": "world3",
            "next": null
        }
    }
}