code: def test_mae_two():
      mae = pm.mae([1, 2], [1, 2])
      assert isinstance(mae, float)
      assert mae == approx(0)
  
      mae = pm.mae([1, 1], [2, 2])
      assert mae == approx(1)
  
      mae = pm.mae([1, 3], [3, 1])
      assert mae == approx(2)
  
      mae = pm.mae([1, 3], [3, 2])
      assert mae == approx(1.5)
  
imports: import numpy
  import pandas
  import os.path
  from pytest import approx, raises, mark, skip
  import lenskit.metrics.predict
  import lenskit.util.test
label_desc: Use image node_id 14 for calling a global function with example usage: test_mae_two() without return types