title: python async def how to return value
body: <p>I am trying to return a list of XHR urls from Python Async. Below is my code.</p>
  
  <pre><code>import asyncio
  from pyppeteer import launch
  
  async def intercept_response(res):
      resourceType = res.request.resourceType
      xhr_list = []
      if resourceType in ['xhr']:
          print(res.request.url)
          xhr_list.append(res.request.url)
      return xhr_list
  
  async def main():
      browser = await launch(headless=False)
      page = await browser.newPage()
      page.on('response', intercept_response)
      await page.setUserAgent('Mozilla/5.0 (iPhone; CPU iPhone OS 11_0 like Mac OS X) AppleWebKit/604.1.38 (KHTML, like Gecko) Version/11.0 Mobile/15A372 Safari/604.1')
      await page.goto('https://www.iesdouyin.com/share/user/70015326114', waitUntil = 'networkidle2')
      await browser.close()
  
  if __name__ == '__main__':
      url = asyncio.run(main())
      print(url)
  </code></pre>
  
  <p>However, when I run the code, res.request.url got printed out, but xhr_list is not returned, causing url to be None. Is there something wrong with my code? </p>