```coffeescript
Backbone.Factlink ||= {}

do ->
  #options:
  #  parentView: marionette view
  #  tooltipViewFactory: -> view
  #  selector: selector identifying what can be hovered over.
  #  $offsetParent: a dom node within which to position the
  #    tooltip with respect to the target (hovered) node. By
  #    default, uses parentView.$el.

  Backbone.Factlink.Tooltip = (options) ->
    positionedRegion = null


    maker = ($el, $target) ->
      throw "Cannot open duplicate tooltip" if positionedRegion?
      regionOptions = _.extend {}, options,
        contentView: options.tooltipViewFactory()

      positionedRegion =
        new Backbone.Factlink.PositionedRegion regionOptions
      positionedRegion.bindToElement $target,
        options.$offsetParent || $el
      positionedRegion.show new PopoverView regionOptions
      positionedRegion.updatePosition()
      positionedRegion.$el

    remover = ->
      positionedRegion.resetFade()
      positionedRegion = null


    closeHandler = Backbone.Factlink.TooltipJQ
      $el: options.parentView.$el
      selector: options.selector
      makeTooltip: maker
      removeTooltip: remover

    options.parentView.on 'close', closeHandler.close




```

Remove unnecessary do nesting; there are no private variables in this scope.
user
```coffeescript
Backbone.Factlink ||= {}

#options:
#  parentView: marionette view
#  tooltipViewFactory: -> view
#  selector: selector identifying what can be hovered over.
#  $offsetParent: a dom node within which to position the
#    tooltip with respect to the target (hovered) node. By
#    default, uses parentView.$el.

Backbone.Factlink.Tooltip = (options) ->
  positionedRegion =
    new Backbone.Factlink.PositionedRegion options

  maker = ($el, $target) ->
    popoverOptions = _.extend {}, options,
      contentView: options.tooltipViewFactory()

    positionedRegion.bindToElement $target,
      options.$offsetParent || $el
    positionedRegion.show new PopoverView popoverOptions
    positionedRegion.updatePosition()
    positionedRegion.$el

  remover = ->
    positionedRegion.resetFade()


  closeHandler = Backbone.Factlink.TooltipJQ
    $el: options.parentView.$el
    selector: options.selector
    makeTooltip: maker
    removeTooltip: remover

  options.parentView.on 'close', closeHandler.close




```
assistant