code: def _load_config(self):
          
          logger.debug(
              'Listing per-account config subdirectories in %s', self._conf_dir
          )
          for acct_id in os.listdir(self._conf_dir):
              path = os.path.join(self._conf_dir, acct_id)
              # skip if not a directory
              if not os.path.isdir(path):
                  continue
              # skip if doesn't match ^[0-9]+$
              if not self.acct_id_re.match(acct_id):
                  continue
              # call _load_account specifying the directory name (acct ID) & path
              self._load_account(acct_id, path)
          # Once all configuration is loaded, build a dict of Account Name to
          # Account ID (``self._acct_name_to_id``) for faster access to configs
          # by name.
          for acct_id, data in self._config.items():
              if data['name'] is None:
                  continue
              self._acct_name_to_id[data['name']] = acct_id
docs: load configuration from config/