title: Why does this Python boolean comparison return a triple?
body: <p>I was playing around on the command-line for Python 2.7.8, where I encountered this behavior:</p>
  
  <pre><code>&gt;&gt;&gt; "902".isdigit() == True
  True
  &gt;&gt;&gt; "902".isdigit(), "2".isdigit() == True
  (True, True)
  &gt;&gt;&gt; "902".isdigit(), "2".isdigit() == True,True
  (True, True, True)
  &gt;&gt;&gt; ("902".isdigit(), "2".isdigit()) == (True,True)
  </code></pre>
  
  <p>I found this surprising. I would have expected <code>&gt;&gt;&gt; "902".isdigit(), "2".isdigit() == True,True</code> to simply return <code>True</code> as if I had surrounded both expressions in parentheses to make them into tuples. Why does Python return this tuple of booleans, rather than a single one? What boolean comparisons does this tuple represent?</p>