<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _on_library_name_changed(self, renderer, path, new_library_name):
 """Callback handling a change of a library name :param Gtk.CellRenderer renderer: Cell renderer showing the library name :param path: Path of library within the list store :param str new_library_name: New library name """

        old_library_name = self.library_list_store[int(path)][self.KEY_STORAGE_ID]
        if old_library_name == new_library_name:
            return
        library_path = self.library_list_store[int(path)][self.VALUE_STORAGE_ID]

        library_config = self.core_config_model.get_current_config_value("LIBRARY_PATHS", use_preliminary=True,
                                                                         default={})
        del library_config[old_library_name]
        library_config[new_library_name] = library_path
        self.core_config_model.set_preliminary_config_value("LIBRARY_PATHS", library_config)
        self._select_row_by_column_value(self.view['library_tree_view'], self.library_list_store,
                                         self.KEY_STORAGE_ID, new_library_name)