public Promise<Void> add(UUID uuid, long amount) {
        Objects.requireNonNull(uuid, "uuid");
        if (amount == 0) {
            return Promise.completed(null);
        }
        if (amount < 0) {
            throw new IllegalArgumentException("amount < 0");
        }

        return doAdd(uuid, amount);
    }
Adds the specified {@code amount}.

@param uuid the uuid
@param amount the amount to add
@return a promise encapsulating the operation
helper-sql/src/main/java/me/lucko/helper/sql/util/Uuid2PosLongTable.java