VertexGradientPlugin Error in Unity 2018.4.5

Assets/CharTween/Scripts/VertexGradientPlugin.cs(14,18): error CS0534: `CharTween.VertexGradientPlugin' does not implement inherited abstract member `DG.Tweening.Plugins.Core.ABSTweenPlugin<TMPro.VertexGradient,TMPro.VertexGradient,DG.Tweening.Plugins.Options.NoOptions>.SetFrom(DG.Tweening.Core.TweenerCore<TMPro.VertexGradient,TMPro.VertexGradient,DG.Tweening.Plugins.Options.NoOptions>, TMPro.VertexGradient, bool)'

[Lir10]

For me it worked by adding the following:

        public override void SetFrom(TweenerCore<VertexGradient, VertexGradient, NoOptions> t, VertexGradient vg, bool  setImmediately, bool isRelative)
        {
            var prevEndVal = t.endValue;
            t.endValue = t.getter();
            t.startValue = isRelative ? Add(t.endValue, prevEndVal) : prevEndVal;
            t.startValue = prevEndVal;
            t.setter(t.startValue);
        }

        public override void SetFrom(TweenerCore<VertexGradient, VertexGradient, NoOptions> t, bool isRelative)
        {
            var prevEndVal = t.endValue;
            t.endValue = t.getter();
            t.startValue = isRelative ? Add(t.endValue, prevEndVal) : prevEndVal;
            t.startValue = prevEndVal;
            t.setter(t.startValue);
        }

[archgame]

Adding the following code in the VertexGradientPlugin class, fixed it for me

public override void SetFrom(TweenerCore<VertexGradient, VertexGradient, NoOptions> t, VertexGradient vg, bool isRelative)
        {
            var prevEndVal = t.endValue;
            t.endValue = t.getter();
            t.startValue = isRelative ? Add(t.endValue, prevEndVal) : prevEndVal;
            t.startValue = prevEndVal;
            t.setter(t.startValue);
        }