code: def test_mae_series_two():
      mae = pm.mae(pd.Series([1, 2]), pd.Series([1, 2]))
      assert isinstance(mae, float)
      assert mae == approx(0)
  
      mae = pm.mae(pd.Series([1, 1]), pd.Series([2, 2]))
      assert mae == approx(1)
  
      mae = pm.mae(pd.Series([1, 3]), pd.Series([3, 1]))
      assert mae == approx(2)
  
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 16 for calling a global function with example usage: test_mae_series_two() without return types