How to use the @lumino/algorithm.iterItems function in @lumino/algorithm

let {storeId, patch} = transaction;

    try {
      this._initTransaction(
        transaction.id,
        Math.max(this._context.version, transaction.version)
      );
    } catch (e) {
      // Already in a transaction. Put the transaction in the queue to apply
      // later.
      this._queueTransaction(transaction, type);
      return;
    }
    let change: Datastore.MutableChange = {};
    try {
      each(iterItems(patch), ([schemaId, tablePatch]) => {
        let table = this._tables.get(schemaId, Private.recordIdCmp);
        if (table === undefined) {
          console.warn(
            `Missing table for schema id '${
              schemaId
            }' in transaction '${transaction.id}'`);
          this._finalizeTransaction();
          return;
        }
        if ( type === 'transaction' || type === 'redo') {
          let count = this._cemetery[transaction.id];
          if (count === undefined) {
            this._cemetery[transaction.id] = 1;
            change[schemaId] = Table.patch(table, tablePatch);
            return;
          }