code: func (s *CredentialHelpers) Reject(what Creds) error {
  	for i, h := range s.helpers {
  		if s.skipped(i) {
  			continue
  		}
  
  		if err := h.Reject(what); err != credHelperNoOp {
  			return err
  		}
  	}
  
  	return errors.New("no valid credential helpers to reject")
  }
docs: // Reject implements CredentialHelper.Reject and rejects the given Creds "what"
  // with the first successful attempt.