code: def test_mae(self) -> None:
      mae = cflearn.api.make_metric("mae")
      labels = np.array([1, 1, 1, 1]).reshape([4, 1])
      predictions = np.array([-0.2, -0.1, 0.1, 0.2]).reshape([4, 1])
      self.assertAlmostEqual(_get_score(mae, predictions, labels), -1.0)
  
file_path: carefree-learn/tests/test_metrics.py
imports: import cflearn
  import unittest
  import numpy
  from cflearn.schema import IMetric
  from cflearn.constants import LABEL_KEY
  from cflearn.constants import PREDICTIONS_KEY
label_desc: Use image node_id 3 for calling the TestMetrics obj's underlying member method code with example usage: obj.test_mae() without return types