code: def timestamp_feature(catalog, soup):
      
      # there's really no "time created", we're using the date the courses are listed for...
      epoch = 1318790434
      catalog.timestamp = int(float(soup.title.text)) + epoch
      catalog.datetime = datetime.datetime.fromtimestamp(catalog.timestamp)
      logger.info('Catalog last updated on %s' % catalog.datetime)
docs: The datetime the xml file was last modified.