code: function fill(iterable, value, start=0, end=iterable.size) {
    let num = end - start
    return iterable.splice(start, num, ...Repeat(value, num))
  }
docs: Fills elements of `iterable` with `value` from `start` up to, but not
  including, `end`.
  
  @static
  @memberOf _
  @category Iterable
  @param {Iterable} iterable The iterable to fill.
  @param {*} value The value to fill `iterable` with.
  @param {number} [start=0] The start position.
  @param {number} [end=iterable.size] The end position.
  @returns {Iterable} Returns `iterable`.
  @example
  
  let list = [1, 2, 3]
  
  _.fill(list, 'a')
  // => ['a', 'a', 'a']
  
  _.fill([4, 6, 8, 10], '*', 1, 3)
  // => [4, '*', '*', 10]