code: def is_valid(self) -> bool:
      if self._error_network is None:
          raise Exception("invalid usage: must query server")
      return self._error_network
  
file_path: wandb/wandb/sdk/lib/server.py
imports: import json
  from typing import TYPE_CHECKING, Any, Dict, Optional, Union
  from wandb import util
  from wandb.apis import InternalApi
label_desc: Use image node_id 3 for calling the Server obj's underlying member method code with example usage: obj.is_valid() and returns: self