title: Find timezone time difference using pytz
body: <p>I am creating a naive datetime object which contains no timezone information, but I know that it is always in UTC. I want to calculate the time difference between local time and UTC for any timezone I define, which would take into account DST as well. </p>
  
  <p>What I am thus doing is the following:</p>
  
  <pre><code>from datetime import datetime, timedelta
  
  now = datetime(2018,3,27,15,20)           #Create a naive datetime object
  now_utc = timezone("UTC").localize(now)   # Add UTC timezone information to it
  now_madrid = now_utc.astimezone(timezone("Europe/Madrid")) # convert to Madrid timezone
  </code></pre>
  
  <p>Normally, if I was to calculate the time difference between two datetime objects I would subtract them. But when I try <code>diff = now_utc -  now_madrid</code> , the result is the following:</p>
  
  <pre><code>In [275]: now_utc-now_madrid
  Out[275]: datetime.timedelta(0)
  </code></pre>
  
  <p>Can anyone please tell me, how I could find the timezone difference in this case? Thank you in advance :)</p>