docs: def retrieve_object(model, *args, **kwargs):
      """
      Retrieves a specific object from a given model by primary-key
      lookup, and stores it in a context variable.
      
      Syntax::
      
          {% retrieve_object [app_name].[model_name] [lookup kwargs] as [varname] %}
      
      Example::
      
          {% retrieve_object flatpages.flatpage pk=12 as my_flat_page %}
      
      """
      if len(args) == 1:
          kwargs.update({'pk': args[0]})
      _model = _get_model(model)
      try:
          return _model._default_manager.get(**kwargs)
      except _model.DoesNotExist:
          return ''