function Grid(gridModel, ecModel, api) {
    /**
     * @type {Object.<string, module:echarts/coord/cartesian/Cartesian2D>}
     * @private
     */
    this._coordsMap = {};

    /**
     * @type {Array.<module:echarts/coord/cartesian/Cartesian>}
     * @private
     */
    this._coordsList = [];

    /**
     * @type {Object.<string, Array.<module:echarts/coord/cartesian/Axis2D>>}
     * @private
     */
    this._axesMap = {};

    /**
     * @type {Array.<module:echarts/coord/cartesian/Axis2D>}
     * @private
     */
    this._axesList = [];

    this._initCartesian(gridModel, ecModel, api);

    this.model = gridModel;
}
@return {Array.<module:echarts/coord/Axis>}