old_contents: from google.appengine.ext import db
  from google.appengine.api.users import User
  
  class Cfp(db.Model):
      name = db.StringProperty()
      fullname = db.StringProperty()
      website = db.LinkProperty()
      begin_conf_date = db.DateProperty()
      end_conf_date = db.DateProperty()
      submission_deadline = db.DateProperty()
      notification_date = db.DateProperty()
      country = db.StringProperty()
      city = db.StringProperty()
      rate = db.RatingProperty()
      submitters = db.ListProperty(User)
      category = db.StringProperty()
      keywords = db.StringListProperty()
      last_update = db.DateTimeProperty(auto_now=True)
  
      def setWebsite(self, link):
          self.website = db.Link(link)
  
      def setAcceptanceRate(self, rate):
          self.rate = db.Rating(rate)
  
      def rfc3339_update():
          return last_update.strftime('%Y-%m-%dT%H:%M:%SZ')
  
new_contents: from google.appengine.ext import db
  from google.appengine.api.users import User
  
  class Cfp(db.Model):
      name = db.StringProperty()
      fullname = db.StringProperty()
      website = db.LinkProperty()
      begin_conf_date = db.DateProperty()
      end_conf_date = db.DateProperty()
      submission_deadline = db.DateProperty()
      notification_date = db.DateProperty()
      country = db.StringProperty()
      city = db.StringProperty()
      rate = db.RatingProperty()
      submitters = db.ListProperty(User)
      category = db.StringProperty()
      keywords = db.StringListProperty()
      last_update = db.DateTimeProperty(auto_now=True)
  
      def setWebsite(self, link):
          self.website = db.Link(link)
  
      def setAcceptanceRate(self, rate):
          self.rate = db.Rating(rate)
  
      def rfc3339_update(self):
          return self.last_update.strftime('%Y-%m-%dT%H:%M:%SZ')
  
subject: Correct bug introduced in the previous commit (last update in feed entries).