docs: def _read_mat_mnu0(filename):
      """Import a .mat file with single potentials (A B M) into a pandas
      DataFrame
  
      Also export some variables of the md struct into a separate structure
      """
      print('read_mag_single_file')
  
      mat = sio.loadmat(filename)
  
      df_emd = _extract_emd(mat)
  
      return df_emd