title: How to get all text between just two specified tags using BeautifulSoup?
body: <pre><code>html = """
  ...
  &lt;tt class="descname"&gt;all&lt;/tt&gt;
  &lt;big&gt;(&lt;/big&gt;
  &lt;em&gt;iterable&lt;/em&gt;
  &lt;big&gt;)&lt;/big&gt;
  &lt;a class="headerlink" href="#all" title="Permalink to this definition"&gt;¶&lt;/a&gt;
  ...
  """
  </code></pre>
  
  <p>I want to get all text between starting tag <code>big</code> upto before the first occurrence of <code>a</code> tag. This means if I take this example, then i must get <code>(iterable)</code> as a string.</p>