new_contents: from uliweb import Middleware, error
  from uliweb.orm import NotFound
  
  class ORMNotfoundMiddle(Middleware):
      ORDER = 110
      
      def __init__(self, application, settings):
          pass
          
      def process_exception(self, request, exception):
          if isinstance(exception, NotFound):
              error("%s(%s) can't be found" % (exception.model.__name__, exception.id))
          
subject: add middle_notfound middleware