code: public Tabs listTabs(String accountId, String envelopeId, String recipientId) throws ApiException {
      return listTabs(accountId, envelopeId, recipientId, null);
    }
docs: Gets the tabs information for a signer or sign-in-person recipient in an envelope.
  Retrieves information about the tabs associated with a recipient in a draft envelope.
  @param accountId The external account number (int) or account ID Guid. (required)
  @param envelopeId The envelopeId Guid of the envelope being accessed. (required)
  @param recipientId The ID of the recipient being accessed. (required)
  @return Tabs