After the seller receives LC advice from the confirming bank, the seller ships the goods. In this step, we define the SellerDeliverGoods transaction and related event for the LC update:

transaction SellerDeliverGoods {
  --> LetterOfCredit lc
  o String evidence
}

event SellerDeliverGoodsEvent {
  --> LetterOfCredit lc
}

The letter status is set to DELIVER_PRODUCT, and the step to 4:

/**
  * seller deliver product
  * @param {org.example.lc.SellerDeliverGoods} sellerDeliverGoods - seller deliver product
  * @transaction
  */
async function sellerDeliverGoods(request) { // eslint-disable-line no-unused-vars
    const factory = getFactory();
    const namespace = 'org.example.lc';

    let letter = request.lc;

    if (letter.status === 'CLOSED') {
        throw new Error ('This letter of credit has already been closed');
    } else if (letter.step!== 3) {
        throw new Error ('This letter of credit should be in step 3 - ADVICE_LC');
    }
    letter.status = 'DELIVER_PRODUCT';
    letter.step=4;
    letter.evidence.push(request.evidence);
    const assetRegistry = await getAssetRegistry(request.lc.getFullyQualifiedType());
    await assetRegistry.update(letter);

    // emit event
    const sellerDeliverGoodsEvent = factory.newEvent(namespace, 'SellerDeliverGoodsEvent');
    sellerDeliverGoodsEvent.lc = letter;
    emit(sellerDeliverGoodsEvent);
}