code: def test_ndcg():
      actual = m.discounted_cum_gain(
          normalized=True, full_dataset=dataset
      )
      expected = 0.9205433036318259
  
imports: from aif360.metrics import RegressionDatasetMetric
  from aif360.datasets import RegressionDataset
  import numpy
  import pandas
label_desc: Use image node_id 3 for calling a global function with example usage: test_ndcg() without return types