     }
 
     /**
-     TODO: docstring
-     
-     - parameter index: The index of the note in the specified note set.
-     - parameter setIndex: The index of the note set holding the note.
+     Returns tie state of note at `index`.
+     
+     - parameter index: Note index.
+     - parameter setIndex: Note set index.
      */
     private func tieState(for index: Int, inSet setIndex: Int) throws -> Tie? {
         return try note(at: index, inSet: setIndex).tie

    }

    /**
     TODO: docstring
     
     - parameter index: The index of the note in the specified note set.
     - parameter setIndex: The index of the note set holding the note.

    }

    /**
     Prepare notes for replacement to make sure the tie state of the notes being replaced is
     preserved in the `newCollections` replacement.

     - parameter range: Note range of notes being replaced.
     - parameter newCollections: New notes to use in replacement.
     - parameter setIndex: Note set index.
     - throws:
         - `MeasureError.invalidNoteCollection` If `noteCollections` is empty.
         - `MeasureError.internalError`
