code: def _read_hdf_columns(path_or_buf, columns, num_splits, kwargs):  # pragma: no cover
      
  
      df = pandas.read_hdf(path_or_buf, columns=columns, **kwargs)
      # Append the length of the index here to build it externally
      return _split_result_for_readers(0, num_splits, df) + [len(df.index)]
docs: Use a Ray task to read columns from HDF5 into a Pandas DataFrame.
  
      Note: Ray functions are not detected by codecov (thus pragma: no cover)
  
      Args:
          path_or_buf: The path of the HDF5 file.
          columns: The list of column names to read.
          num_splits: The number of partitions to split the column into.
  
      Returns:
           A list containing the split Pandas DataFrames and the Index as the last
              element. If there is not `index_col` set, then we just return the length.
              This is used to determine the total length of the DataFrame to build a
              default Index.