How to use the @here/harp-materials.EdgeMaterial.DEFAULT_COLOR function in @here/harp-materials

const fadeFar =
            technique.fadeFar !== undefined
                ? getPropertyValue(technique.fadeFar, displayZoomLevel)
                : FadingFeature.DEFAULT_FADE_FAR;

        const lineFadeNear =
            technique.lineFadeNear !== undefined
                ? getPropertyValue(technique.lineFadeNear, displayZoomLevel)
                : fadeNear;
        const lineFadeFar =
            technique.lineFadeFar !== undefined
                ? getPropertyValue(technique.lineFadeFar, displayZoomLevel)
                : fadeFar;

        if (color === undefined) {
            color = EdgeMaterial.DEFAULT_COLOR;
        }

        return {
            color,
            colorMix,
            fadeNear,
            fadeFar,
            lineFadeNear,
            lineFadeFar
        };
    }
}