   #
   # If the given checkpoint is no longer present in the undo history, this
   # method will return an empty {Array}.
+  #
+  # * `checkpoint` {Number} id of the checkpoint to get changes since.
   #
   # Returns an {Array} of {Object}s with the following fields that summarize
   #  the aggregated changes since the checkpoint. See *Working With Aggregated

  # undo history, no changes will be made to the buffer and this method will
  # return `false`.
  #
  # Returns a {Boolean} indicating whether the operation succeeded.
  revertToCheckpoint: (checkpoint, options) ->
    if truncated = @historyProvider.revertToCheckpoint(checkpoint, options)
      @emitWillChangeEvent()
      @transactCallDepth++
      try

  # Public: Create a pointer to the current state of the buffer for use
  # with {::revertToCheckpoint} and {::groupChangesSinceCheckpoint}.
  #
  # Returns a checkpoint id value.
  createCheckpoint: ->
    @historyProvider.createCheckpoint(markers: @createMarkerSnapshot(), isBarrier: false)

