code: func NewTransactionOrDie(ctx context.Context, store Store, params ...TransactionParams) Transaction {
  	txn, err := store.NewTransaction(ctx, params...)
  	if err != nil {
  		panic(err)
  	}
  	return txn
  }
docs: // NewTransactionOrDie is a helper function to create a new transaction. If the
  // storage layer cannot create a new transaction, this function will panic. This
  // function should only be used for tests.