code: def normalize(dt, tz):
      
      if not isinstance(tz, tzinfo):
          tz = pytz.timezone(tz)
      dt = tz.normalize(dt)
      return dt
docs: Given a object with a timezone return a datetime object
      normalized to the proper timezone.
  
      This means take the give localized datetime and returns the
      datetime normalized to match the specificed timezone.