transaction:
{
  "id": "add-items-to-basket",
    "operations": [
    {
      operationRefId: "catalog-get-items",
      id: "op-1",
    },
    {
      operationRefId: "op-id-2",
      id: "second-op-in-this-transaction",
      arguments: [ 
	userId, 
	@first-op-in-this-transaction.response.id
      ]
    }
  ]
}