Get a single record from the API.

        Args:
            model_class (:class:`cinder_data.model.CinderModel`): A subclass of
                :class:`cinder_data.model.CinderModel` of your chosen model.
            record_id (int): The id of the record requested.

        Returns:
            :class:`cinder_data.model.CinderModel`: An instance of model_class or None.

def _get_record(self, model_class, record_id):
        """Get a single record from the API.

        Args:
            model_class (:class:`cinder_data.model.CinderModel`): A subclass of
                :class:`cinder_data.model.CinderModel` of your chosen model.
            record_id (int): The id of the record requested.

        Returns:
            :class:`cinder_data.model.CinderModel`: An instance of model_class or None.
        """
        url = '{host}/{namespace}/{model}/{id}'.format(
            host=self._host,
            namespace=self._namespace,
            model=self._translate_name(model_class.__name__),
            id=record_id
        )
        data = self._get_json(url)['data']
        fresh_model = model_class(data['attributes'])
        fresh_model.id = data['id']
        fresh_model.validate()
        if self._cache is not None:
            self._cache.set_record(model_class.__name__, fresh_model.id, fresh_model)
        return fresh_model