title: Get URL from BeautifulSoup object
body: <p>Somebody is handing my function a BeautifulSoup object (BS4) that he has gotten using the typical call:</p>
  
  <pre><code>soup = BeautifulSoup(url)
  </code></pre>
  
  <p>my code:</p>
  
  <pre><code>def doSomethingUseful(soup):
      url = soup.???
  </code></pre>
  
  <p>How do I get the original URL from the soup object? I tried reading the docs AND the BeautifulSoup source code... I'm still not sure.</p>