code: def set_dataset_root(root_dir: str):
      """Set the default dataset root directory.
  
      :param root_dir: The new root directory.
      """
      AVALANCHE_CONFIG["dataset_location"] = root_dir
  
imports: from pathlib import Path
  import json
  import os
label_desc: Use image node_id 1 for calling a global function with example usage: set_dataset_root(root_dir) without return types