class_docstr: Implementation of HpoExecutor Interface, where our custom logic is used as the backend
code: def executor_type(self):
      return CUSTOM_BACKEND
  
imports: from __future__ import annotations
  import copy
  import logging
  import math
  import os
  import time
  from abc import ABC, abstractmethod
  from typing import TYPE_CHECKING, Any, Callable, Dict, List, Optional, Tuple, Union
  import pandas
  from autogluon.common import space
  from autogluon.common.utils.resource_utils import ResourceManager
  from autogluon.common.utils.s3_utils import is_s3_url
  from ..ray.resources_calculator import ResourceCalculator
  from ..scheduler.scheduler_factory import scheduler_factory
  from ..utils.savers import save_pkl
  from .constants import CUSTOM_BACKEND, RAY_BACKEND
  from .exceptions import EmptySearchSpace
label_desc: Use image node_id 2 for calling the CustomHpoExecutor obj's underlying member method code with example usage: obj.executor_type() and returns: CUSTOM_BACKEND