@delegate_manager
    def root_node(self, tree_id):
        return self._mptt_filter(tree_id=tree_id, parent=None).get()
:type content: dict
dataset/ETHPy150Open django-mptt/django-mptt/mptt/managers.py/TreeManager.root_node--crossover with--dataset/ETHPy150Open pcn/pyKairosDB/pyKairosDB/util.py/get_content_values_by_name