title: How to test the membership of multiple values in a list
body: <p>I want to test if two or more values have membership on a list, but I'm getting an unexpected result:</p>
  <pre><code>&gt;&gt;&gt; 'a','b' in ['b', 'a', 'foo', 'bar']
  ('a', True)
  </code></pre>
  <p>So, Can Python test the membership of multiple values at once in a list?
  What does that result mean?</p>
  <hr />
  <p><sub>See also: <a href="https://stackoverflow.com/questions/3697432">How to find list intersection?</a>. Checking whether <em>any</em> of the specified values is in the list, is equivalent to checking if the intersection is non-empty. Checking whether <em>all</em> the values are in the list, is equivalent to checking if they are a subset.</sub></p>