old_contents: # -*- coding: utf-8 -*-
  __author__ = 'sandlbn'
  
  from django.db import models
  from django.utils.translation import ugettext_lazy as _
  from utils import datetime_to_timestamp
  
  
  class CalendarEvent(models.Model):
      """
      Calendar Events
      """
      CSS_CLASS_CHOICES = (
          ('', _('Normal')),
          ('event-warning', _('Warning')),
          ('event-info', _('Info')),
          ('event-success', _('Success')),
          ('event-inverse', _('Inverse')),
          ('event-special', _('Special')),
          ('event-important', _('Important')),
      )
      title = models.CharField(max_length=255, verbose_name=_('Title'))
      url = models.URLField(verbose_name=_('URL'), null=True, blank=True)
      css_class = models.CharField(max_length=20, verbose_name=_('CSS Class'),
                                   choices=CSS_CLASS_CHOICES)
      start = models.DateTimeField(verbose_name=_('Start Date'))
      end = models.DateTimeField(verbose_name=_('End Date'), null=True,
                                 blank=True)
  
      @property
      def start_timestamp(self):
          """
          Return end date as timestamp
          """
          return datetime_to_timestamp(self.start)
  
      @property
      def end_timestamp(self):
          """
          Return end date as timestamp
          """
          return datetime_to_timestamp(self.end)
  
      def __unicode__(self):
          return self.title
  
new_contents: # -*- coding: utf-8 -*-
  __author__ = 'sandlbn'
  
  from django.db import models
  from django.utils.translation import ugettext_lazy as _
  from utils import datetime_to_timestamp
  
  
  class CalendarEvent(models.Model):
      """
      Calendar Events
      """
      CSS_CLASS_CHOICES = (
          ('', _('Normal')),
          ('event-warning', _('Warning')),
          ('event-info', _('Info')),
          ('event-success', _('Success')),
          ('event-inverse', _('Inverse')),
          ('event-special', _('Special')),
          ('event-important', _('Important')),
      )
      title = models.CharField(max_length=255, verbose_name=_('Title'))
      url = models.URLField(verbose_name=_('URL'), null=True, blank=True)
      css_class = models.CharField(blank=True, max_length=20, verbose_name=_('CSS Class'),
                                   choices=CSS_CLASS_CHOICES)
      start = models.DateTimeField(verbose_name=_('Start Date'))
      end = models.DateTimeField(verbose_name=_('End Date'), null=True,
                                 blank=True)
  
      @property
      def start_timestamp(self):
          """
          Return end date as timestamp
          """
          return datetime_to_timestamp(self.start)
  
      @property
      def end_timestamp(self):
          """
          Return end date as timestamp
          """
          return datetime_to_timestamp(self.end)
  
      def __unicode__(self):
          return self.title
  
subject: Allow `css_class` to have blank value.