title: Insert a tzinfo into datetime
body: <p>I have the following <code>tzinfo</code> concrete subclass definition:</p>
  
  <pre><code>from datetime import datetime, timedelta, tzinfo
  
  class ManilaTime(tzinfo):
    def utcoffset(self, dt):
      return timedelta(hours=8)
  
    def tzname(self, dt):
      return "Manila"
  </code></pre>
  
  <p>I obtain a date string and would like to transform it into a timezone-aware <code>datetime</code> object. I prefer to use the following method:</p>
  
  <pre><code>def transform_date(date_string, tzinfo):
    fmt = '%Y-%m-%d'
    # Where do I insert tzinfo?
    date = datetime.strptime(date_string, fmt)
    return date
  </code></pre>
  
  <p>Is there some way I could insert the <code>tzinfo</code> into the <code>datetime</code> object in the following manner?</p>
  
  <pre><code>manila = ManilaTime()
  date = transform_date('2001-01-01', manila)
  </code></pre>