How to use the @nivo/bump.AreaBumpDefaultProps.startLabelTextColor function in @nivo/bump

key: 'startLabelPadding',
        group: 'Labels',
        type: 'number',
        defaultValue: defaults.startLabelPadding,
        controlType: 'range',
        controlOptions: {
            min: 0,
            max: 30,
        },
    },
    {
        key: 'startLabelTextColor',
        help: 'Method to compute start label text color.',
        type: 'string | object | Function',
        required: false,
        defaultValue: defaults.startLabelTextColor,
        controlType: 'inheritedColor',
        group: 'Labels',
    },
    {
        key: 'endLabel',
        group: 'Labels',
        type: 'false | string | (serie: Serie) => string',
        defaultValue: defaults.endLabel,
    },
    {
        key: 'endLabelPadding',
        group: 'Labels',
        type: 'number',
        defaultValue: defaults.endLabelPadding,
        controlType: 'range',
        controlOptions: {

colors: { scheme: 'nivo' },
    blendMode: 'multiply',
    fillOpacity: AreaBumpDefaultProps.fillOpacity,
    activeFillOpacity: AreaBumpDefaultProps.activeFillOpacity,
    inactiveFillOpacity: AreaBumpDefaultProps.inactiveFillOpacity,
    borderWidth: AreaBumpDefaultProps.borderWidth,
    activeBorderWidth: AreaBumpDefaultProps.activeBorderWidth,
    inactiveBorderWidth: AreaBumpDefaultProps.inactiveBorderWidth,
    borderColor: AreaBumpDefaultProps.borderColor,
    borderOpacity: AreaBumpDefaultProps.borderOpacity,
    activeBorderOpacity: AreaBumpDefaultProps.activeBorderOpacity,
    inactiveBorderOpacity: AreaBumpDefaultProps.inactiveBorderOpacity,

    startLabel: 'id',
    startLabelPadding: AreaBumpDefaultProps.startLabelPadding,
    startLabelTextColor: AreaBumpDefaultProps.startLabelTextColor,
    endLabel: 'id',
    endLabelPadding: AreaBumpDefaultProps.endLabelPadding,
    endLabelTextColor: AreaBumpDefaultProps.endLabelTextColor,

    enableGridX: AreaBumpDefaultProps.enableGridX,
    axisTop: {
        enable: true,
        tickSize: 5,
        tickPadding: 5,
        tickRotation: 0,
        legend: '',
        legendPosition: 'middle',
        legendOffset: -36,
    },
    axisBottom: {
        enable: true,