docs: def read_time_h5(h5folder):
      """Iterate through (isnap, istep) recorded in h5folder/'time_botT.h5'.
  
      Args:
          h5folder (:class:`pathlib.Path`): directory of HDF5 output files.
      Yields:
          tuple of int: (isnap, istep).
      """
      with h5py.File(h5folder / 'time_botT.h5', 'r') as h5f:
          for name, dset in h5f.items():
              yield int(name[-5:]), int(dset[2])