How to return a custom value from a custom Nightwatch command?

[MurzNN]

I need to create a Nightwatch command that returns a custom value, instead of the browser object, something like this - file tests/Nightwatch/Commands/myTestCommand.js:

exports.command = function myTestCommand() {
  return 'foo';
}

And the test:

module.exports = {
  '@tags': ['my_test'],
  'My test': async (browser) => {
    const myValue = browser.myTestCommand();
    console.log('myValue', myValue);
  },
};

But the custom command myTestCommand returns not the string 'foo', but the NightwatchAPI (browser) object, here is the output:

myValue NightwatchAPI {
  capabilities: {
    acceptInsecureCerts: false,
    acceptSslCerts: false,
...
  _axeInjectFn: [Function: bound queuedCommandFn]
}

So, how can I receive the foo string return value instead of the browser object in my custom command?