This is also significant reason why people have problem when migrating py2 code to py3. The code is actually buggy and mixes strings with bytes. Once they run it in Py3 all of the bugs show up because Py3 is stricter about it.<p>For the same reason if you need to write code that should work on Py2 and Py3, it&#x27;s much easier to write it on Py3 and then add backward compatibility through &quot;from __future__ import ...&quot; and the six module.