title: Checking if a date string is in UTC format
body: <p>I have a date string like "2011-11-06 14:00:00+00:00". Is there a way to check if this is in UTC format or not ?. I tried to convert the above string to a datetime object using <code>utc = datetime.strptime('2011-11-06 14:00:00+00:00','%Y-%m-%d %H:%M%S+%z)</code> so that i can compare it with pytz.utc, but i get 'ValueError: 'z' is a bad directive in format '%Y-%m-%d %H:%M%S+%z'</p>
  
  <p>How to check if the date string is in UTC ?. Some example would be really appreciated.</p>
  
  <p>Thank You</p>