code: def fetch(clobber=False):
      
  
      dest_dir = fname_pattern = os.path.join(data_dir(), 'chen2014')
      url = 'http://lamost973.pku.edu.cn/site/Photometric-Extinctions-and-Distances/table2.dat'
      dat_fname = os.path.join(dest_dir, 'chen2014.dat')
      h5_fname = os.path.join(dest_dir, 'chen2014.h5')
      md5 = 'f8a2bc46d411c57ca4c76dc344e291f1'
  
      # Check if file already exists
      if not clobber:
          h5_size = 52768768 # Guess, in Bytes
          h5_dsets = {
              'dists': (30,),
              'pix_lb': (557398, 2),
              'A_r': (557398, 30),
              'A_r_err': (557398, 30)
          }
          if fetch_utils.h5_file_exists(h5_fname, h5_size, dsets=h5_dsets):
              print('File appears to exist already. Call `fetch(clobber=True)` '
                    'to force overwriting of existing file.')
              return
  
      # Download the table
      print('Downloading {}'.format(url))
      fetch_utils.download_and_verify(url, md5, fname=dat_fname)
  
      # Convert from ASCII to HDF5 format
      print('Repacking files...')
      ascii2h5(dat_fname, h5_fname)
  
      # Cleanup
      print('Removing original file...')
      os.remove(dat_fname)
docs: Downloads the Chen et al. (2014) dust map.
  
      Args:
          clobber (Optional[:obj:`bool`]): If ``True``, any existing file will be
              overwritten, even if it appears to match. If ``False`` (the
              default), :obj:`fetch()` will attempt to determine if the dataset
              already exists. This determination is not 100\% robust against data
              corruption.