code: def get_method_sub_patt(self, test_id, subtest_id):
      self.write(f"get_sub_value_{test_id}_{subtest_id}")
  
file_path: mars/mars/services/web/tests/test_core.py
imports: import asyncio
  import os
  import sys
  import pytest
  from tornado import httpclient
  from ....None import oscar
  from ....utils import get_next_port
  from ..None import WebActor, web_api, MarsServiceWebAPIHandler, MarsWebAPIClientMixin
  from ..api.web import MarsApiEntryHandler
label_desc: Use image node_id 3 for calling the TestAPIHandler obj's underlying member method code with example usage: obj.get_method_sub_patt(test_id, subtest_id) without return types