expected assignment or function call no-unused-expressions ReactJS

Question

This is my code:

class Game extends Component 
{
  constructor() 
  {
    super()
    this.state = {
      speed: 0
    }
    //firebaseInit()
  }
  render()
  {
    return 
    (
      <div>
        <h1>The Score is {this.state.speed};</h1>
      </div>
    )
  }
}

export default Game;

I am getting this error when I execute the above code:

Expected an assignment or function call and instead saw an expression  no-unused-expressions

What is the problem with the code?