def _load_cache(self):
        """Load existing cache and merge for updating if required."""
        if not self._disable_cache:
            if os.path.exists(self._cache_path):
                _LOGGER.debug("Cache found at: %s", self._cache_path)
                if os.path.getsize(self._cache_path) > 0:
                    loaded_cache = UTILS.load_cache(self._cache_path)
                    UTILS.update(self._cache, loaded_cache)
                else:
                    _LOGGER.debug("Cache file is empty.  Removing it.")
                    os.remove(self._cache_path)

        self._save_cache()