Класс SingleObjectTemplateResponseMixin (Django 3.0)

def get_template_names(self):
    """
    Return a list of template names to be used for the request. May not be
    called if render_to_response() is overridden. Return the following list:
    * the value of ``template_name`` on the view (if provided)
    * the contents of the ``template_name_field`` field on the
      object instance that the view is operating upon (if available)
    * ``<app_label>/<model_name><template_name_suffix>.html``
    """
    try:
        names = super().get_template_names()
    except ImproperlyConfigured:
        # If template_name isn't specified, it's not a problem --
        # we just start with an empty list.
        names = []
        # If self.template_name_field is set, grab the value of the field
        # of that name from the object; this is the most specific template
        # name, if given.
        if self.object and self.template_name_field:
            name = getattr(self.object, self.template_name_field, None)
            if name:
                names.insert(0, name)
        # The least-specific option is the default <app>/<model>_detail.html;
        # only use this if the object in question is a model.
        if isinstance(self.object, models.Model):
            object_meta = self.object._meta
            names.append("%s/%s%s.html" % (
                object_meta.app_label,
                object_meta.model_name,
                self.template_name_suffix
            ))
        elif getattr(self, 'model', None) is not None and issubclass(self.model, models.Model):
            names.append("%s/%s%s.html" % (
                self.model._meta.app_label,
                self.model._meta.model_name,
                self.template_name_suffix
            ))
        # If we still haven't managed to find any template names, we should
        # re-raise the ImproperlyConfigured to alert the user.
        if not names:
            raise
    return names

def get_template_names(self):
    """
    Return a list of template names to be used for the request. Must return
    a list. May not be called if render_to_response() is overridden.
    """
    if self.template_name is None:
        raise ImproperlyConfigured(
            "TemplateResponseMixin requires either a definition of "
            "'template_name' or an implementation of 'get_template_names()'")
    else:
        return [self.template_name]