_init(node) {
        if (!node) node = {
            name: "sst",
            attributes: {
                xmlns: "http://schemas.openxmlformats.org/spreadsheetml/2006/main"
            },
            children: []
        };

        this._node = node;

        delete this._node.attributes.count;
        delete this._node.attributes.uniqueCount;
    }
Initialize the node.
@param {{}} [node] - The shared strings node.
@private
@returns {undefined}