code: def _get_dataset_url(name, dataset_dir: dict = None):
      r"""
      给定dataset的名称，返回下载url
  
      :param str name: 给定dataset的名称，比如imdb, sst-2等
      :return: str
      """
      #  从扩展中寻找下载的url
      url = _read_extend_url_file(FASTNLP_EXTEND_DATASET_URL, name)
      if url:
          return url
  
      dataset_dir = DATASET_DIR if dataset_dir is None else dataset_dir
      filename = dataset_dir.get(name, None)
      if filename:
          url = _get_base_url("dataset") + filename
          return url
      else:
          raise KeyError(f"There is no {name}.")
  
imports: import os
  import re
  import shutil
  import tempfile
  from pathlib import Path
  from urllib.parse import urlparse
  import requests
  from requests import HTTPError
  from fastNLP.core.log import logger
  from rich.progress import Progress, BarColumn, DownloadColumn, TimeRemainingColumn, TimeElapsedColumn
label_desc: Use image node_id 7 for calling a global function with example usage: _get_dataset_url(name, dataset_dir) and returns: url, url