如何在python中做三维数组中的连通组件标记？

def mark_connected_components(arr):
    def dfs(i, j, k, label):
        if i < 0 or i >= len(arr) or j < 0 or j >= len(arr[0]) or k < 0 or k >= len(arr[0][0]) or arr[i][j][k] != 1:
            return
        arr[i][j][k] = label
        dfs(i+1, j, k, label)
        dfs(i-1, j, k, label)
        dfs(i, j+1, k, label)
        dfs(i, j-1, k, label)
        dfs(i, j, k+1, label)
        dfs(i, j, k-1, label)

    label = 2
    for i in range(len(arr)):
        for j in range(len(arr[0])):
            for k in range(len(arr[0][0])):
                if arr[i][j][k] == 1:
                    dfs(i, j, k, label)
                    label += 1

# 示例用法
arr = [
    [[1, 0, 0], [0, 1, 1], [0, 0, 0]],
    [[0, 0, 1], [1, 0, 0], [0, 1, 0]],
    [[0, 1, 0], [0, 0, 1], [1, 1, 1]]
]
mark_connected_components(arr)
print(arr)