Restore all items expanded state

def restore_expanded_state(self):
        """Restore all items expanded state"""
        if self.__expanded_state is not None:
            # In the old project explorer, the expanded state was a dictionnary:
            if isinstance(self.__expanded_state, list):
                self.fsmodel.directoryLoaded.connect(
                                                  self.restore_directory_state)
                self.fsmodel.directoryLoaded.connect(
                                                self.follow_directories_loaded)