How to check if a list ONLY contains a certain item
<p>I have a list called bag. I want to be able to check if only a particular item is in it.</p>

<pre><code>bag = ["drink"]
if only "drink" in bag:
    print 'There is only a drink in the bag'
else:
    print 'There is something else other than a drink in the bag'
</code></pre>

<p>Of course, where I put 'only' in the code there, it is wrong. Is there any simple replacement of that? I have tried a few similar words.</p>