<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def get_levels_of_description(self):
 """ Returns an array of all levels of description defined in this AtoM instance. """

        if not hasattr(self, "levels_of_description"):
            self.levels_of_description = [
                item["name"]
                for item in self._get(urljoin(self.base_url, "taxonomies/34")).json()
            ]

        return self.levels_of_description