code: def healthcheck(self) -> Optional[HealthcheckResponse]:
      try:
          resp = requests.get(self._url("/api/healthcheck"))
          resp.raise_for_status()
          return HealthcheckResponse.parse_obj(resp.json())
      except requests.exceptions.RequestException:
          return None
  
imports: import asyncio
  import weakref
  from typing import BinaryIO, Dict, Optional, Union
  import aiohttp
  import requests
  import requests.exceptions
  from dstack._internal.core.models.repos.remote import RemoteRepoCreds
  from dstack._internal.core.models.runs import JobSpec, RunSpec
  from dstack._internal.server.schemas.runner import HealthcheckResponse, PullResponse, RegistryAuthBody, SubmitBody
label_desc: Use image node_id 2 for calling the RunnerClient obj's underlying member method code with example usage: obj.healthcheck() and returns: HealthcheckResponse, None