How to use the @nivo/calendar.CalendarDefaultProps.dayBorderColor function in @nivo/calendar

},
    {
        key: 'dayBorderWidth',
        help: 'width of days border.',
        type: 'number',
        required: false,
        defaultValue: defaults.dayBorderWidth,
        controlType: 'lineWidth',
        group: 'Days',
    },
    {
        key: 'dayBorderColor',
        help: 'color to use for days border.',
        type: 'string',
        required: false,
        defaultValue: defaults.dayBorderColor,
        controlType: 'colorPicker',
        group: 'Days',
    },
    {
        key: 'isInteractive',
        flavors: ['svg', 'canvas'],
        help: 'Enable/disable interactivity.',
        type: 'boolean',
        required: false,
        defaultValue: defaults.isInteractive,
        controlType: 'switch',
        group: 'Interactivity',
    },
    {
        key: 'onClick',
        flavors: ['svg', 'canvas'],