code: def is_model(model_name: str) -> bool:
      """Check if a model name exists"""
      arch_name = get_arch_name(model_name)
      return arch_name in _model_entrypoints
  
imports: import fnmatch
  import re
  import sys
  import warnings
  from collections import defaultdict, deque
  from copy import deepcopy
  from dataclasses import replace
  from typing import Any, Callable, Dict, Iterable, List, Optional, Set, Sequence, Union, Tuple
  from ._pretrained import PretrainedCfg, DefaultCfg
label_desc: Use image node_id 12 for calling a global function with example usage: is_model(model_name) and returns: unknown