new_contents: from comics.aggregator.crawler import CrawlerBase, CrawlerImage
  from comics.meta.base import MetaBase
  
  class Meta(MetaBase):
      name = 'Sheldon'
      language = 'en'
      url = 'http://www.sheldoncomics.com/'
      start_date = '2001-11-30'
      rights = 'Dave Kellett'
  
  class Crawler(CrawlerBase):
      history_capable_date = Meta.start_date
      schedule = 'Mo,Tu,We,Th,Fr,Sa,Su'
      time_zone = -5
  
      def crawl(self, pub_date):
          filetype = 'gif'
          if pub_date.weekday() in [5,6]: filetype = 'jpg'
          url = 'http://www.sheldoncomics.com/strips/%s.%s' % (
                  pub_date.strftime('sd%y%m%d'), filetype)
          title = 'strip for %s' % pub_date.strftime('%B / %d / %Y')
          return CrawlerImage(url, title)
  
subject: Add sheldon (sheldoncomics.com)