在react with hooks and bootstrap中，如何在accordion打开时更改V形？

npm install react-bootstrap

import React from 'react';
import { Accordion, Card } from 'react-bootstrap';
import 'bootstrap/dist/css/bootstrap.min.css';

const [isOpen, setIsOpen] = React.useState(false);

<Accordion>
  <Card>
    <Accordion.Toggle
      as={Card.Header}
      eventKey="0"
      onClick={() => setIsOpen(!isOpen)}
    >
      Accordion Title
    </Accordion.Toggle>
    <Accordion.Collapse eventKey="0">
      <Card.Body>
        Accordion Content
      </Card.Body>
    </Accordion.Collapse>
  </Card>
</Accordion>

<Accordion.Toggle
  as={Card.Header}
  eventKey="0"
  onClick={() => setIsOpen(!isOpen)}
>
  {isOpen ? '▲' : '▼'} Accordion Title
</Accordion.Toggle>