docs: def dataset_archive(dataset, signature, data_home=None, ext=".zip"):
      """
      Checks to see if the dataset archive file exists in the data home directory,
      found with ``get_data_home``. By specifying the signature, this function
      also checks to see if the archive is the latest version by comparing the
      sha256sum of the local archive with the specified signature.
  
      Parameters
      ----------
      dataset : str
          The name of the dataset; should either be a folder in data home or
          specified in the yellowbrick.datasets.DATASETS variable.
  
      signature : str
          The SHA 256 signature of the dataset, used to determine if the archive
          is the latest version of the dataset or not.
  
      data_home : str, optional
          The path on disk where data is stored. If not passed in, it is looked
          up from YELLOWBRICK_DATA or the default returned by ``get_data_home``.
  
      ext : str, default: ".zip"
          The extension of the archive file.
  
      Returns
      -------
      exists : bool
          True if the dataset archive exists and is the latest version.
      """
      data_home = get_data_home(data_home)
      path = os.path.join(data_home, dataset+ext)
  
      if os.path.exists(path) and os.path.isfile(path):
          return sha256sum(path) == signature
  
      return False