title: How to compute the time difference between two time zones in python?
body: <p>How can I compute the time differential between two time zones in Python? That is, I don't want to compare TZ-aware <code>datetime</code> objects and get a <code>timedelta</code>; I want to compare two <code>TimeZone</code> objects and get an <code>offset_hours</code>. Nothing in the <code>datetime</code> library handles this, and neither does <a href="https://pypi.python.org/pypi/pytz" rel="noreferrer"><code>pytz</code></a>.</p>