在2标签beautifulsoup python之前解析

我想提取所有链接http://example.com/1并忽略带有beautifulsoup的2 <br><br> 标签后的所有链接 .

<div class="compost">
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index18" class="select_index"></span>text 2</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index19" class="select_index"></span>text 3</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index20" class="select_index"></span>text 4</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index21" class="select_index"></span>text 5</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index22" class="select_index"></span>text 6</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index23" class="select_index"></span>text 7</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index24" class="select_index"></span>text 8</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index25" class="select_index"></span>text 9</a></b>
<br>
<br>
<b><a target="_blank" href="http://example.com/2"><span id="s_index18" class="select_index"></span>text 2</a></b>
<br><b><a target="_blank" href="http://example.com/2"><span id="s_index19" class="select_index"></span>text 3</a></b>
<br><b><a target="_blank" href="http://example.com/2"><span id="s_index20" class="select_index"></span>text 4</a></b>
<br><b><a target="_blank" href="http://example.com/2"><span id="s_index21" class="select_index"></span>text 5</a></b>
<br><b><a target="_blank" href="http://example.com/2"><span id="s_index22" class="select_index"></span>text 6</a></b>
<br><b><a target="_blank" href="http://example.com/2"><span id="s_index23" class="select_index"></span>text 7</a></b>
<br><b><a target="_blank" href="http://example.com/2"><span id="s_index24" class="select_index"></span>text 8</a></b>
<br><b><a target="_blank" href="http://example.com/2"><span id="s_index25" class="select_index"></span>text 9</a></b>
<br>
<br>
<b><a target="_blank" href="http://example.com/3"><span id="s_index18" class="select_index"></span>text 2</a></b>
<br><b><a target="_blank" href="http://example.com/3"><span id="s_index19" class="select_index"></span>text 3</a></b>
<br><b><a target="_blank" href="http://example.com/3"><span id="s_index20" class="select_index"></span>text 4</a></b>
<br><b><a target="_blank" href="http://example.com/3"><span id="s_index21" class="select_index"></span>text 5</a></b>
<br><b><a target="_blank" href="http://example.com/3"><span id="s_index22" class="select_index"></span>text 6</a></b>
<br><b><a target="_blank" href="http://example.com/3"><span id="s_index23" class="select_index"></span>text 7</a></b>
<br><b><a target="_blank" href="http://example.com/3"><span id="s_index24" class="select_index"></span>text 8</a></b>
<br><b><a target="_blank" href="http://example.com/3"><span id="s_index25" class="select_index"></span>text 9</a></b>
<br>
<br>

这是我需要解析的部分：

<br><b><a target="_blank" href="http://example.com/1"><span id="s_index18" class="select_index"></span>text 2</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index19" class="select_index"></span>text 3</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index20" class="select_index"></span>text 4</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index21" class="select_index"></span>text 5</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index22" class="select_index"></span>text 6</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index23" class="select_index"></span>text 7</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index24" class="select_index"></span>text 8</a></b>
<br><b><a target="_blank" href="http://example.com/1"><span id="s_index25" class="select_index"></span>text 9</a></b>

这是我的代码的一部分

for links in obja.find_all("div", class_="compost"):
        if links.has_attr('href'):
            print links['href']
        #
        aa = links.findAll('a')[0]
        print aa.attrs['href']
        txt = []
        for i in links.findAll('br'):
            txt.append(i.text)
            print i.nextSibling
            if i.nextSibling.text != u'br':
                txt.append(i.nextSibling.text)

        ''.join(txt)

我的脚本提取所有链接，我不知道如何提取所有http://example.com/1并忽略 <br><br> 之后的所有链接？