def _get_next_tree_id(self):
        max_tree_id = list(self.aggregate(Max(self.tree_id_attr)).values())[0]
        max_tree_id = max_tree_id or 0
        return max_tree_id + 1
Returns a compilation level for Closure Compiler.
dataset/ETHPy150Open django-mptt/django-mptt/mptt/managers.py/TreeManager._get_next_tree_id--crossover with--dataset/ETHPy150Open googkit/googkit/googkit/lib/config.py/Config.compilation_level