code: async def async_fetch(url: str, **kwargs) -> Selector:
      
      kwargs.setdefault('headers', DEFAULT_HEADERS)
      async with aiohttp.ClientSession(**kwargs) as ses:
          async with ses.get(url, **kwargs) as res:
              html = await res.text()
              tree = Selector(text=html)
              return tree
docs: Do the fetch in an async style.
  
      Args:
          url (str): The url of the site.
  
      Returns:
          Selector: allows you to select parts of HTML text using CSS or XPath expressions.