code: def flatten_dict(d, parent_key="", sep="_"):
      """Flatten a nested dictionary.
  
      Based on https://stackoverflow.com/a/6027615/5703449
      """
      items = []
      for k, v in d.items():
          new_key = parent_key + sep + k if parent_key else k
          if isinstance(v, dict):
              items.extend(
                  flatten_dict(v, parent_key=new_key, sep=sep).items()
              )
          else:
              items.append((new_key, v))
      return dict(items)
  
label_desc: Use image node_id 1 for calling a global function with example usage: flatten_dict(d, parent_key, sep) and returns: dict