catextlayer - CATextLayer は NSMutableParagraphStyle を無視しています

Question

NSMutableAttributedStringテキストでテキストを描画するために使用したいCATextLayer。のような font や fontcolor に属性を設定しようとしNSMutableAttributedStringました[attrString setAttributes:attributes range:range];が、 のすべての属性NSMutableParagraphStyleが無視されます。

let str = "I want to use NSMutableAttributedString to draw the text on the CATextLayer with the text. I try set attributes to the like font and fontcolor of the NSMutableAttributedString through the [attrString setAttributes:attributes range:range]; but all attributes in the NSMutableParagraphStyle are ignored."
    let att = NSMutableAttributedString(string: str)
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.lineSpacing = 12
    att.addAttribute(NSParagraphStyleAttributeName, value: paragraphStyle, range: NSMakeRange(0, str.characters.count))
let contentLayer = initTextLayer("", andFontSize: 11)
    contentLayer.string = att
    contentLayer.frame = CGRect(x: 30 * AUTOSIZESCALEX, y: CGRectGetMaxY(titleLayer.frame) + 15 * AUTOSIZESCALEY, width: SCREEN_WIDTH - 60 * AUTOSIZESCALEX, height: 200 * AUTOSIZESCALEY)
    self.contentView.layer.addSublayer(contentLayer)

func initTextLayer(title: String, andFontSize size: CGFloat) -> CATextLayer{
    let textLayer = CATextLayer()
    textLayer.foregroundColor = UIColor(hexString: "333333").CGColor
    textLayer.string = title
    textLayer.alignmentMode = kCAAlignmentLeft
    textLayer.contentsScale = UIScreen.mainScreen().scale
    textLayer.shouldRasterize = false
    textLayer.wrapped = true
    textLayer.fontSize = size  * AUTOSIZESCALEY
    return textLayer
}

私が間違っていることはありますか？