old_contents: """
  Add a "featured" field to objects so admins can better direct top content.
  """
  
  from __future__ import absolute_import, unicode_literals
  
  from django.db import models
  from django.utils.translation import ugettext_lazy as _
  
  from feincms import extensions
  
  
  class Extension(extensions.Extension):
      def handle_model(self):
          self.model.add_to_class('featured', models.BooleanField(_('featured')))
  
          if hasattr(self.model, 'cache_key_components'):
              self.model.cache_key_components.append(lambda page: page.featured)
  
      def handle_modeladmin(self, modeladmin):
          modeladmin.add_extension_options(_('Featured'), {
              'fields': ('featured',),
              'classes': ('collapse',),
          })
  
new_contents: """
  Add a "featured" field to objects so admins can better direct top content.
  """
  
  from __future__ import absolute_import, unicode_literals
  
  from django.db import models
  from django.utils.translation import ugettext_lazy as _
  
  from feincms import extensions
  
  
  class Extension(extensions.Extension):
      def handle_model(self):
          self.model.add_to_class(
              'featured',
              models.BooleanField(
                  _('featured'),
                  default=False,
              ),
          )
  
          if hasattr(self.model, 'cache_key_components'):
              self.model.cache_key_components.append(lambda page: page.featured)
  
      def handle_modeladmin(self, modeladmin):
          modeladmin.add_extension_options(_('Featured'), {
              'fields': ('featured',),
              'classes': ('collapse',),
          })
  
subject: Fix #597: Boolean fields require default values