How to use the lib0/prng.js.int31 function in lib0

function insertTypeArray (user, gen) {
    const yarray = user.getArray('array')
    var pos = prng.int31(gen, 0, yarray.length)
    yarray.insert(pos, [new Y.Array()])
    var array2 = yarray.get(pos)
    array2.insert(0, [1, 2, 3, 4])
  },
  function insertTypeMap (user, gen) {

function insertTypeMap (user, gen) {
    const yarray = user.getArray('array')
    var pos = prng.int31(gen, 0, yarray.length)
    yarray.insert(pos, [new Y.Map()])
    var map = yarray.get(pos)
    map.set('someprop', 42)
    map.set('someprop', 43)
    map.set('someprop', 44)
  },
  function _delete (user, gen) {

function _delete (user, gen) {
    const yarray = user.getArray('array')
    var length = yarray.length
    if (length > 0) {
      var somePos = prng.int31(gen, 0, length - 1)
      var delLength = prng.int31(gen, 1, math.min(2, length - somePos))
      if (prng.bool(gen)) {
        var type = yarray.get(somePos)
        if (type.length > 0) {
          somePos = prng.int31(gen, 0, type.length - 1)
          delLength = prng.int31(gen, 0, math.min(2, type.length - somePos))
          type.delete(somePos, delLength)
        }
      } else {
        yarray.delete(somePos, delLength)
      }
    }
  }
]

function _delete (user, gen) {
    const yarray = user.getArray('array')
    var length = yarray.length
    if (length > 0) {
      var somePos = prng.int31(gen, 0, length - 1)
      var delLength = prng.int31(gen, 1, math.min(2, length - somePos))
      if (prng.bool(gen)) {
        var type = yarray.get(somePos)
        if (type.length > 0) {
          somePos = prng.int31(gen, 0, type.length - 1)
          delLength = prng.int31(gen, 0, math.min(2, type.length - somePos))
          type.delete(somePos, delLength)
        }
      } else {
        yarray.delete(somePos, delLength)
      }
    }
  }
]

function insert (user, gen) {
    const yarray = user.getArray('array')
    var uniqueNumber = getUniqueNumber()
    var content = []
    var len = prng.int31(gen, 1, 4)
    for (var i = 0; i < len; i++) {
      content.push(uniqueNumber)
    }
    var pos = prng.int31(gen, 0, yarray.length)
    yarray.insert(pos, content)
  },
  function insertTypeArray (user, gen) {

function insert (user, gen) {
    const yarray = user.getArray('array')
    var uniqueNumber = getUniqueNumber()
    var content = []
    var len = prng.int31(gen, 1, 4)
    for (var i = 0; i < len; i++) {
      content.push(uniqueNumber)
    }
    var pos = prng.int31(gen, 0, yarray.length)
    yarray.insert(pos, content)
  },
  function insertTypeArray (user, gen) {

function _delete (user, gen) {
    const yarray = user.getArray('array')
    var length = yarray.length
    if (length > 0) {
      var somePos = prng.int31(gen, 0, length - 1)
      var delLength = prng.int31(gen, 1, math.min(2, length - somePos))
      if (prng.bool(gen)) {
        var type = yarray.get(somePos)
        if (type.length > 0) {
          somePos = prng.int31(gen, 0, type.length - 1)
          delLength = prng.int31(gen, 0, math.min(2, type.length - somePos))
          type.delete(somePos, delLength)
        }
      } else {
        yarray.delete(somePos, delLength)
      }
    }
  }
]

function _delete (user, gen) {
    const yarray = user.getArray('array')
    var length = yarray.length
    if (length > 0) {
      var somePos = prng.int31(gen, 0, length - 1)
      var delLength = prng.int31(gen, 1, math.min(2, length - somePos))
      if (prng.bool(gen)) {
        var type = yarray.get(somePos)
        if (type.length > 0) {
          somePos = prng.int31(gen, 0, type.length - 1)
          delLength = prng.int31(gen, 0, math.min(2, type.length - somePos))
          type.delete(somePos, delLength)
        }
      } else {
        yarray.delete(somePos, delLength)
      }
    }
  }
]