code: def test_get_scorer():
      with pytest.raises(ValueError):
          get_scorer("unknown")
  
      assert get_scorer("r2") is not None
      assert get_scorer(r2_score) is not None
  
imports: import pytest
  from sklearn.metrics import r2_score
  from ..None import get_scorer
label_desc: Use image node_id 1 for calling a global function with example usage: test_get_scorer() without return types