About Formatting: The empty line dilemma

formatting-empty-lines.scala

def copyFrom
   (source: ReadOnlySpace[ShapeT],
    sourceRegion: CellBox = null,
    destination: Int3 = this.lower): Unit = {

  val sourceBounds =
    if (sourceRegion != null) {
      Check.argument(source.bounds contains sourceRegion)
      sourceRegion
    } else
      source.bounds

  val translation = destination - sourceBounds.lower

  Check.argument(bounds contains (sourceBounds move translation),
    s"Destination region (${sourceBounds move translation}) doesn't fit within destination space")

  Check.argument(source zoneIsolated sourceBounds,
    "Some shapes in source space intersects boundaries of source region")

  for (cell <- sourceBounds.iterateCells) {
    val shape = source.at(cell)
    if (shape != null)
      insertOrReplace(source.centerOfShapeAt(cell) + translation, shape)
    else
      remove(cell + translation)
  }
}