code: def _fetch_model(model_name) -> str:
      model_map = {}
  
      hu_path: str = (
          "https://nlp.informatik.hu-berlin.de/resources/models"
      )
  
      model_map["relations"] = "/".join(
          [hu_path, "relations", "relations-v11.pt"]
      )
  
      cache_dir = Path("models")
      if model_name in model_map:
          model_name = cached_path(
              model_map[model_name], cache_dir=cache_dir
          )
  
      return model_name
  
file_path: flair/flair/models/relation_extractor_model.py
imports: import logging
  from pathlib import Path
  from typing import Any, Dict, List, Optional, Set, Tuple, Union
  import torch
  import flair.embeddings
  import flair.nn
  from flair.data import Relation, Sentence
  from flair.file_utils import cached_path
label_desc: Use image node_id 8 for calling the RelationExtractor obj's underlying member method code with example usage: obj._fetch_model(model_name) and returns: model_name