[
  [
    8,
    [],
    [
      -1,
      -2,
      null
    ],
    [],
    [],
    [
      null,
      "k1",
      null,
      null
    ],
    [
      null,
      1,
      null,
      null
    ],
    -1,
    [],
    [],
    [],
    [],
    []
  ]
]