old_contents: from django.utils.decorators import available_attrs
  from django.utils.http import urlquote
  from django.http import HttpResponse
  from django.template import loader, RequestContext
  
  from functools import wraps
  
  def singleton(cls):
      instances = {}
      def getinstance():
          if cls not in instances:
              instances[cls] = cls()
          return instances[cls]
      return getinstance
  
  def authorized(test_func, template_name='401.html'):
      """
      Decorator for views that checks that the user passes the given test,
      redirecting to the unauthorized page if it fails. The test should be a
      callable that takes the user object and returns True if the user passes.
      """
  
      def decorator(view_func):
          def _wrapped_view(request, *args, **kwargs):
              if test_func(request.user, *args, **kwargs):
                  return view_func(request, *args, **kwargs)
              path = urlquote(request.get_full_path())
              t = loader.get_template(template_name)
              return HttpResponse(t.render(RequestContext(request)), status=401)
          return wraps(view_func,
                  assigned=available_attrs(view_func))(_wrapped_view)
      return decorator
  
new_contents: from django.shortcuts import get_object_or_404
  from django.utils.decorators import available_attrs
  from django.utils.http import urlquote
  from django.http import HttpResponse
  from django.template import loader, RequestContext
  
  from functools import wraps
  
  def singleton(cls):
      instances = {}
      def getinstance():
          if cls not in instances:
              instances[cls] = cls()
          return instances[cls]
      return getinstance
  
  def authorized(test_func, template_name='401.html'):
      """
      Decorator for views that checks that the user passes the given test,
      redirecting to the unauthorized page if it fails. The test should be a
      callable that takes the user object and returns True if the user passes.
      """
  
      def decorator(view_func):
          def _wrapped_view(request, *args, **kwargs):
              if test_func(request.user, *args, **kwargs):
                  return view_func(request, *args, **kwargs)
              path = urlquote(request.get_full_path())
              t = loader.get_template(template_name)
              return HttpResponse(t.render(RequestContext(request)), status=401)
          return wraps(view_func,
                  assigned=available_attrs(view_func))(_wrapped_view)
      return decorator
  
  def load_instance(model):
      def decorator(view):
          def _wrapper(request, object_id=None, *args, **kwargs):
              if object_id:
                  instance = get_object_or_404(model, pk=object_id)
                  return view(request, instance, *args, **kwargs)
              return view(request, *args, **kwargs)
          return wraps(view)(_wrapper)
      return decorator
  
subject: Add decorator for loading instance of a model in a view.