code: def variables(self):
          
          url = self.base_url + 'ts'
          headers = {'Authorization': 'Bearer {}'.format(self.auth())}
          r = requests.get(url, headers=headers)
          df = pd.read_json(r.content, orient='records')
          return pd.Series(df['variable'].unique(), name='variable')
docs: All variables in the connected data source