def get_template_names(self):
        """
        Returns a set of template names that may be used when rendering
        the response.
        """
        if self.template_name is not None:
            return [self.template_name]

        msg = (
            "'%s' must either define 'template_name' or override "
            + "'get_template_names()'"
        )
        raise ImproperlyConfigured(msg % self.__class__.__name__)

        Returns a set of template names that may be used when rendering
        the response.
        
vanilla/views.py