如何修改网格线样式？

```kotlin
aaOptions.xAxis?.apply {
            labels(aaLabelsX)
                .lineColor("#CFCFCF")  // x轴的颜色
                .lineWidth(0.5)
                .gridLineDashStyle("LongDash")
                .gridLineWidth(2)
                .minorGridLineDashStyle("LongDash")
                .minorGridLineWidth(2)
        }
```

设置无效