code: def test_dcg():
      actual = m.discounted_cum_gain(normalized=False)
      expected = 2.6126967369231484
      assert abs(actual - expected) < 1e-6
  
imports: from aif360.metrics import RegressionDatasetMetric
  from aif360.datasets import RegressionDataset
  import numpy
  import pandas
label_desc: Use image node_id 2 for calling a global function with example usage: test_dcg() without return types