A related, albeit simpler, Python quirk.<p><pre><code>  &gt;&gt;&gt; a = 100
  &gt;&gt;&gt; b = 100
  &gt;&gt;&gt; a is b
  True
  &gt;&gt;&gt; a = 1000
  &gt;&gt;&gt; b = 1000
  &gt;&gt;&gt; a is b
  False</code></pre>