import fromEvent from 'xstream/extra/fromEvent' not working in Opera 68

[ovidiugabriel]

import fromEvent from 'xstream/extra/fromEvent'

Uncaught SyntaxError: Cannot use import statement outside a module

I am following the tutorial at https://egghead.io/lessons/rxjs-read-effects-from-the-dom-with-click-events
It looks like fromEvent is not Rx.Observable.fromEvent either.