docs: def save_dict_to_hdf5(dic, filename):
      """
      ....
      """
      with h5py.File(filename, 'w') as h5file:
          rf = recursively_save_dict_contents_to_group(h5file, '/', dic)
          h5_rf = h5file.create_group("_reconstruction_flags")
          # h5_rf = h5file.create_group("_reconstruction_key_flags")
          for k, v in rf.items():
              h5_rf.create_dataset("/_reconstruction_flags" + k, data=v)