def load_module(self, path, changed_time, parser=None):
        """Attempts to load the specified module from a serialized, cached
        version. If that fails, the method returns none."""
        if settings.use_filesystem_cache == False:
            return None
        
        try:
            pickle_changed_time = self._index[path]
        except KeyError:
            return None

        if (changed_time is not None and
            pickle_changed_time < changed_time):
            # the pickle file is outdated
            return None

        target_path = self._get_hashed_path(path)
        with open(target_path, 'rb') as f:
            try:
                gc.disable()
                cache_module = pickle.load(f)
                if parser is not None:
                    for mod in cache_module:
                        mod.unpickle(parser)
            finally:
                gc.enable()

        debug.dbg('pickle loaded: %s', path)
        return cache_module
Attempts to load the specified module from a serialized, cached
        version. If that fails, the method returns none.