定义一个对象的属性值相对于它的兄弟是可以的吗?

class App extends React.Component {
  state = {
    tomsWallet: 50,
    hannahsPurse: 49,
  }
  getTotalBalance = () => {
    return (this.state.tomsWallet + this.state.hannahsPurse).toFixed(2);
  }
  render() {
    return (
      <div>Total Balance: £{this.getTotalBalance()}</div>
    )
  }
}

ReactDOM.render(<App/>, document.getElementById('root'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<div id="root"></div>