function setLabelStyle(
    normalStyle, emphasisStyle,
    normalModel, emphasisModel,
    opt,
    normalSpecified, emphasisSpecified
) {
    opt = opt || EMPTY_OBJ;
    var labelFetcher = opt.labelFetcher;
    var labelDataIndex = opt.labelDataIndex;
    var labelDimIndex = opt.labelDimIndex;

    // This scenario, `label.normal.show = true; label.emphasis.show = false`,
    // is not supported util someone requests.

    var showNormal = normalModel.getShallow('show');
    var showEmphasis = emphasisModel.getShallow('show');

    // Consider performance, only fetch label when necessary.
    // If `normal.show` is `false` and `emphasis.show` is `true` and `emphasis.formatter` is not set,
    // label should be displayed, where text is fetched by `normal.formatter` or `opt.defaultText`.
    var baseText;
    if (showNormal || showEmphasis) {
        if (labelFetcher) {
            baseText = labelFetcher.getFormattedLabel(labelDataIndex, 'normal', null, labelDimIndex);
        }
        if (baseText == null) {
            baseText = isFunction$1(opt.defaultText) ? opt.defaultText(labelDataIndex, opt) : opt.defaultText;
        }
    }
    var normalStyleText = showNormal ? baseText : null;
    var emphasisStyleText = showEmphasis
        ? retrieve2(
            labelFetcher
                ? labelFetcher.getFormattedLabel(labelDataIndex, 'emphasis', null, labelDimIndex)
                : null,
            baseText
        )
        : null;

    // Optimize: If style.text is null, text will not be drawn.
    if (normalStyleText != null || emphasisStyleText != null) {
        // Always set `textStyle` even if `normalStyle.text` is null, because default
        // values have to be set on `normalStyle`.
        // If we set default values on `emphasisStyle`, consider case:
        // Firstly, `setOption(... label: {normal: {text: null}, emphasis: {show: true}} ...);`
        // Secondly, `setOption(... label: {noraml: {show: true, text: 'abc', color: 'red'} ...);`
        // Then the 'red' will not work on emphasis.
        setTextStyle(normalStyle, normalModel, normalSpecified, opt);
        setTextStyle(emphasisStyle, emphasisModel, emphasisSpecified, opt, true);
    }

    normalStyle.text = normalStyleText;
    emphasisStyle.text = emphasisStyleText;
}
Set text option in the style.
See more info in `setTextStyleCommon`.
@deprecated
@param {Object} textStyle
@param {module:echarts/model/Model} labelModel
@param {string|boolean} defaultColor Default text color.
       If set as false, it will be processed as a emphasis style.