How to use the @nivo/radar.RadarDefaultProps.borderWidth function in @nivo/radar

description: `
            Defines CSS \`mix-blend-mode\` property, see
            [MDN documentation](https://developer.mozilla.org/fr/docs/Web/CSS/mix-blend-mode).
        `,
        type: 'string',
        required: false,
        defaultValue: defaults.blendMode,
        controlType: 'blendMode',
        group: 'Style',
    },
    {
        key: 'borderWidth',
        help: 'Shape border width.',
        type: 'number',
        required: false,
        defaultValue: defaults.borderWidth,
        controlType: 'lineWidth',
        group: 'Style',
    },
    {
        key: 'borderColor',
        help: 'Method to compute border color.',
        type: 'string | object | Function',
        required: false,
        defaultValue: defaults.borderColor,
        controlType: 'inheritedColor',
        group: 'Style',
    },
    {
        key: 'gridLevels',
        help: 'Number of levels to display for grid',
        type: 'number',