code: def read_cumulative_iss_index():
      "Read in the whole cumulative index and return dataframe."
      indexdir = get_index_dir()
  
      path = indexdir / "COISS_2999_index.hdf"
      try:
          df = pd.read_hdf(path, "df")
      except FileNotFoundError:
          path = indexdir / "cumindex.hdf"
          df = pd.read_hdf(path, "df")
      # replace PDS Nan values (-1e32) with real NaNs
      df = df.replace(-1.000000e32, np.nan)
      return df.replace(-999.0, np.nanf read_cumulative_iss_index():
      "Read in the whole cumulative index and return dataframe."
      indexdir = get_index_dir()
  
      path = indexdir / "COISS_2999_index.hdf"
      try:
          df = pd.read_hdf(path, "df")
      except FileNotFoundError:
          path = indexdir / "cumindex.hdf"
          df = pd.read_hdf(path, "df")
      # replace PDS Nan values (-1e32) with real NaNs
      df = df.replace(-1.000000e32, np.nan)
      return df.replace(-999.0, np.nan)
docs: Read in the whole cumulative index and return dataframe.