如何在swift 3中使用chartView.clear()清除图表，然后向图表中添加数据

let chartView = BarChartView(frame: CGRect(x: 0, y: 0, width: 300, height: 200))
self.view.addSubview(chartView)

chartView.clear()

var dataEntries: [ChartDataEntry] = []
dataEntries.append(ChartDataEntry(x: 1, y: 10))
dataEntries.append(ChartDataEntry(x: 2, y: 20))
dataEntries.append(ChartDataEntry(x: 3, y: 30))

let chartDataSet = BarChartDataSet(entries: dataEntries, label: "Data")

let chartData = BarChartData(dataSet: chartDataSet)

chartView.data = chartData

import UIKit
import Charts

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        let chartView = BarChartView(frame: CGRect(x: 0, y: 0, width: 300, height: 200))
        self.view.addSubview(chartView)
        
        chartView.clear()
        
        var dataEntries: [ChartDataEntry] = []
        dataEntries.append(ChartDataEntry(x: 1, y: 10))
        dataEntries.append(ChartDataEntry(x: 2, y: 20))
        dataEntries.append(ChartDataEntry(x: 3, y: 30))
        
        let chartDataSet = BarChartDataSet(entries: dataEntries, label: "Data")
        let chartData = BarChartData(dataSet: chartDataSet)
        
        chartView.data = chartData
    }
}