code: def test_mean_prediction_unweighted():
      y_pred = [0, 1, 2, 3, 4]
      y_true = None
  
      result = metrics.mean_prediction(y_true, y_pred)
  
      assert result == 2
  
imports: import fairlearn.metrics
label_desc: Use image node_id 1 for calling a global function with example usage: test_mean_prediction_unweighted() without return types