python报错 TypeError: a bytes-like object is required, not ‘ResultSet‘

将BeautifulSoup结果保存到txt时报错

 
     soup = BeautifulSoup(ymt)
     soup.prettify()
     hc = soup.find_all('td')
     f.write(hc)

运行报错TypeError: a bytes-like object is required, not ‘ResultSet’

加一段代码就ok了

    soup = BeautifulSoup(ymt)
    soup.prettify()
    hc = soup.find_all('td')
    hc = ("%s"%hc).encode()
    f.write(hc)