def METHOD_NAME(self):
    """Read the cached DataFrame from file.
    Raises:
      CacheError: if there was a problem reading the cache from file.
    """
    self.check_file()
    try:
        self.df = pd.read_csv(self.filename)
    except Exception:
        raise CacheError(f"Problem reading cache from file {self.filename}")
    self.loaded = True