old_contents: from resync.resource_list import ResourceList
  from resync.resource import Resource
  from resync.sitemap import Sitemap
  
  rl = ResourceList()
  rl.add( Resource('http://example.com/res1', lastmod='2013-01-01') )
  rl.add( Resource('http://example.com/res2', lastmod='2013-01-02') )
  sm = Sitemap(pretty_xml=True)
  print sm.resources_as_xml(rl)
  
new_contents: from resync.resource_list import ResourceList
  from resync.resource import Resource
  from resync.sitemap import Sitemap
  
  rl = ResourceList()
  rl.add( Resource('http://example.com/res1', lastmod='2013-01-01') )
  rl.add( Resource('http://example.com/res2', lastmod='2013-01-02') )
  print rl.as_xml(pretty_xml=True)
  
subject: Update to use ResourceList methods