docs: def download_all(data_home=None, replace=False):
      """
      Downloads all the example datasets to the data directory specified by
      ``get_data_home``. This function ensures that all datasets are available
      for use with the examples.
      """
      for _, meta in DATASETS.items():
          download_data(
              meta['url'], meta['signature'], data_home=data_home, replace=replace
          )
  
      print(
          "Downloaded {} datasets to {}".format(len(DATASETS), get_data_home(data_home))
      )