You may also want to read the note at the bottom of the hint page.
BTW, as long as you call it event inside the handler you should actually have access to the event object without using a parameter.
handleChange() {
console.log('event', event) // the event object should be logged
}
But your event inside the setState updater function isn’t the event, it is the current/previous state.
handleChange() {
this.setState(state => {
console.log('state', state)
})
}