function getSign(data, dataIndex, openVal, closeVal, closeDim) {
    var sign;
    if (openVal > closeVal) {
        sign = -1;
    }
    else if (openVal < closeVal) {
        sign = 1;
    }
    else {
        sign = dataIndex > 0
            // If close === open, compare with close of last record
            ? (data.get(closeDim, dataIndex - 1) <= closeVal ? 1 : -1)
            // No record of previous, set to be positive
            : 1;
    }

    return sign;
}
@constructor
@param {module:echarts/data/List} data
@param {number} idx
@extends {module:zrender/graphic/Group}