code: def to_timezone(dt, timezone):
      
      if dt.tzinfo is None:
          dt = dt.replace(tzinfo=_UTC)
      return timezone.normalize(dt.astimezone(timezone))
docs: Return an aware datetime which is ``dt`` converted to ``timezone``.
  
      If ``dt`` is naive, it is assumed to be UTC.
  
      For example, if ``dt`` is "06:00 UTC+0000" and ``timezone`` is "EDT-0400",
      then the result will be "02:00 EDT-0400".
  
      This method follows the guidelines in http://pytz.sourceforge.net/