title: lxml equivalent to BeautifulSoup "OR" syntax?
body: <p>I'm converting some html parsing code from BeautifulSoup to lxml.  I'm trying to figure out the lxml equivalent syntax for the following BeautifullSoup statement:</p>
  
  <pre><code>soup.find('a', {'class': ['current zzt', 'zzt']})
  </code></pre>
  
  <p>Basically I want to find all of the "a" tags in the document that have a class attribute of either "current zzt" or "zzt".  BeautifulSoup allows one to pass in a list, dictionary, or even a regular express to perform the match.</p>
  
  <p>What is the lxml equivalent?</p>
  
  <p>Thanks!</p>