function verifyColdObjectAvailable(objMD) {
    // return error when object is cold
    if (objMD.archive &&
        // Object is in cold backend
        (!objMD.archive.restoreRequestedAt ||
            // Object is being restored
            (objMD.archive.restoreRequestedAt && !objMD.archive.restoreCompletedAt))) {
        const err = errorInstances.InvalidObjectState
            .customizeDescription('The operation is not valid for the object\'s storage class');
        return err;
    }
    return null;
}
checks if object data is available or if it's in cold storage
@param {ObjectMD} objMD Object metadata
@returns {ArsenalError|null} error if object data is not available