code: def listidentifiers(**kwargs):
      
      e_tree, e_listidentifiers = verb(**kwargs)
      result = get_records(**kwargs)
  
      for record in result.items:
          pid = oaiid_fetcher(record['id'], record['json']['_source'])
          header(
              e_listidentifiers,
              identifier=pid.pid_value,
              datestamp=record['updated'],
              sets=record['json']['_source'].get('_oai', {}).get('sets', []),
          )
  
      resumption_token(e_listidentifiers, result, **kwargs)
      return e_tree
docs: Create OAI-PMH response for verb ListIdentifiers.