code: def test_get_tables(self):
      handler = Mock(GmailHandler)
      tables = handler.get_tables()
      assert tables.type is not RESPONSE_TYPE.ERROR
  
imports: from mindsdb.api.executor.data_types.response_type import RESPONSE_TYPE
  from mindsdb.integrations.handlers.gmail_handler.gmail_handler import GmailHandler
  from mindsdb.integrations.handlers.gmail_handler.gmail_handler import EmailsTable
  from google.oauth2.credentials import Credentials
  from mindsdb_sql import parse_sql
  import unittest
  from unittest.mock import Mock, patch
  from unittest import mock
label_desc: Use image node_id 1 for calling the EmailsTableTest obj's underlying member method code with example usage: obj.test_get_tables() without return types