Goで構造体のスライスを複数のフィールドで並べ替えるにはどうすればよいですか?

type Parent struct {
    id       string
    children []Child
}

type Child struct {
    id string
}

parents := []Parent{
    {
        "3",
        []Child{
            {"2"},
            {"3"},
            {"1"},
        },
    },
    {
        "1",
        []Child{
            {"8"},
            {"9"},
            {"7"},
        },
    },
    {
        "2",
        []Child{
            {"5"},
            {"6"},
            {"4"},
        },
    },
}

<code class="go">// Sort parents by their ID
sort.Slice(parents, func(i, j int) bool { return parents[i].id < parents[j].id })

// Iterate over each parent and sort their children by ID
for _, parent := range parents {
    sort.Slice(parent.children, func(i, j int) bool { return parent.children[i].id < parent.children[j].id })
}</code>

[{1 [{7} {8} {9}]} {2 [{4} {5} {6}]} {3 [{1} {2} {3}]}]