Help with implementing new MergeExpect and MergeTest features

Hi all

I am having trouble implementing the new feature to create and merge multiple custom tests/expects.

I have followed the examples in the documentation and whenever I try and run the tests I am seeing the following error message

SyntaxError: The requested module '@playwright/test' does not provide an export named 'mergeExpects'

fixture.ts

import { mergeExpects, mergeTests } from '@playwright/test';
import { test as baseTest, expect as baseExpect } from './base.js';
import { test as axeTest } from './axe-test.js';
import { test as pageObjectsTest } from './page-objects.js';

export const test = mergeTests(baseTest, pageObjectsTest);// , axeTest);
export const expect = mergeExpects(baseExpect);

I assume it has something to do with the way the project is set up (ESM)