code: def get_root_banks(self):
          
          # Implemented from template for
          # osid.resource.BinHierarchySession.get_root_bins
          if self._catalog_session is not None:
              return self._catalog_session.get_root_catalogs()
          return BankLookupSession(
              self._proxy,
              self._runtime).get_banks_by_ids(list(self.get_root_bank_ids()))
docs: Gets the root banks in this bank hierarchy.
  
          return: (osid.assessment.BankList) - the root banks
          raise:  OperationFailed - unable to complete request
          raise:  PermissionDenied - authorization failure occurred
          *compliance: mandatory -- This method is must be implemented.*