[超初歩的質問] エラーメッセージ "Use of unresolved identifier"

###前提・実現したいこと
swiftで以下のエラーが発生したので取り除きたいです。

###発生している問題・エラーメッセージ

Use of unresolved identifier 'labels'

###ViewController.swift

swift
1import UIKit
2import Anima
3import Charts
4import CoreGraphics
5
6class ViewController2: UIViewController {
7
8    override func viewDidLoad() {
9        super.viewDidLoad()
10
11        // Do any additional setup after loading the view.
12    }
13
14    override func didReceiveMemoryWarning() {
15        super.didReceiveMemoryWarning()
16        // Dispose of any resources that can be recreated.
17    }
18
19    
20    private var animaView: Anima {
21        return animaView
22    }
23    
24    @IBAction func ex3(_ sender: UIButton) {
25        
26        let startAnimations: [AnimaType] = [.moveByY(-50), .rotateByZDegree(90)]
27        let moveAnimations: [AnimaType] = [.moveByX(50), .rotateByZDegree(90)]
28        let endAnimations: [AnimaType] = [.moveByY(-50), .
29            rotateByZDegree(90)]
30       
31        func labelAnimaOption(index: Int) -> [AnimaOption] {
32            let labelAnima = labels[index]?.layer.anima
33            
34            return [.completion({
35                labelAnima?.then(.opacity(1)).fire()
36            })]
37        }
38
39        
40        animaView.layer?.anima
41            .then(.opacity(1.0))
42            .then(group: startAnimations)
43            .then(group: moveAnimations, options: labelAnimaOption(index: 0))
44            .then(group: moveAnimations, options: labelAnimaOption(index: 1))
45            .then(group: moveAnimations, options: labelAnimaOption(index: 2))
46            .then(group: moveAnimations, options: labelAnimaOption(index: 3))
47            .then(group: endAnimations, options: labelAnimaOption(index: 4))
48            .then(group: [.scaleBy(0.0), AnimaType.opacity(0.0)])
49        
50       
51    }
52     
53}
54
55

Charts（ライブラリ）のRadarChartData.swift

swift
1//
2//  RadarChartData.swift
3//  Charts
4//
5//  Copyright 2015 Daniel Cohen Gindi & Philipp Jahoda
6//  A port of MPAndroidChart for iOS
7//  Licensed under Apache License 2.0
8//
9//  https://github.com/danielgindi/Charts
10//
11
12import Foundation
13import CoreGraphics
14
15
16open class RadarChartData: ChartData
17{
18    open var highlightColor = NSUIColor(red: 255.0/255.0, green: 187.0/255.0, blue: 115.0/255.0, alpha: 1.0)
19    open var highlightLineWidth = CGFloat(1.0)
20    open var highlightLineDashPhase = CGFloat(0.0)
21    open var highlightLineDashLengths: [CGFloat]?
22    
23    /// Sets labels that should be drawn around the RadarChart at the end of each web line.
24    open var labels = [String]()
25    
26    /// Sets the labels that should be drawn around the RadarChart at the end of each web line.
27    open func setLabels(_ labels: String...)
28    {
29        self.labels = labels
30    }
31    
32    public override init()
33    {
34        super.init()
35    }
36    
37    public override init(dataSets: [IChartDataSet]?)
38    {
39        super.init(dataSets: dataSets)
40    }
41    
42    open override func entryForHighlight(_ highlight: Highlight) -> ChartDataEntry?
43    {
44        return getDataSetByIndex(highlight.dataSetIndex)?.entryForIndex(Int(highlight.x))
45    }
46}

###試したこと
'labels'で調べるとライブラリであるChartsのRaderChartDataで宣言されたものであった為、importしましたがエラー内容が変わりません。
RaderChartData.swiftのlabelsの宣言方法がopenだったのを変えたり、RaderChartData.swiftでimportしていたライブラリをViewController,swiftの方でimportしてみましたが同じエラーのままです。

どなたか知恵をいただけると幸いです

###補足情報(言語/FW/ツール等のバージョンなど)
より詳細な情報