how to obtain the text for BeautifulSoup object

[Nathan Zhu]

 Hi Team,

could anyone help me?

for webpage having source code like this:
...
<span class="xst thread-name">
    <em>number</em>
    <a class="xst">name</a>
</span>

I only can use below sentence, since there are a lot of tag em and tag a in
other area.
output = bs4.BeautifulSoup(res.content,'lxml').findAll("span",{"class":"xst
thread-name"})

how can I get the text in tag em and tag a under tag span?

thank you for your support!

Nathan