code: def __init__(self, ndcg_at, name="NDCG"):
      self._ndcg_at = np.array(ndcg_at)
  
      super(NDCG, self).__init__(etype="rank", name=name)
  
imports: import numpy
  from math import log
  from openrec.tf1.utils.evaluators import Evaluator
label_desc: Use image node_id 1 to create a new NDCG object from inherited base classes: Evaluator with example: obj = NDCG(ndcg_at, name)