function cellToParent(h3Index, res) {
    const [lower, upper] = h3IndexToSplitLong(h3Index);
    const parent = C._malloc(SZ_H3INDEX);
    try {
        throwIfError(H3.cellToParent(lower, upper, res, parent));
        return validateH3Index(readH3IndexFromPointer(parent));
    } finally {
        C._free(parent);
    }
}
Get the parent of the given hexagon at a particular resolution
@static
@param  {H3IndexInput} h3Index  H3 index to get parent for
@param  {number} res       Resolution of hexagon to return
@return {H3Index}          H3 index of parent, or null for invalid input
@throws {H3Error}          If input is invalid