code: def has_hf_hub(necessary=False):
      if not _has_hf_hub and necessary:
          # if no HF Hub module installed, and it is necessary to continue, raise error
          raise RuntimeError(
              "Hugging Face hub model specified but package not installed. Run `pip install huggingface_hub`."
          )
      return _has_hf_hub
  
imports: import hashlib
  import json
  import logging
  import os
  from functools import partial
  from pathlib import Path
  from tempfile import TemporaryDirectory
  from typing import Iterable, Optional, Union
  import torch
  from torch.hub import HASH_REGEX, download_url_to_file, urlparse
  from timm import __version__
  from timm.models._pretrained import filter_pretrained_cfg
label_desc: Use image node_id 4 for calling a global function with example usage: has_hf_hub(necessary) and returns: _has_hf_hub