code: def is_alnum_or_underscore(ch: str):
      """
      A helper function for checking if a character is alphanumeric or underscore.
      """
      return ch.isalnum() or ch == "_"
  
imports: from typing import Dict, List, Tuple
  import torch.jit
label_desc: Use image node_id 1 for calling a global function with example usage: is_alnum_or_underscore(ch) and returns: unknown