code: def test_prediction_ratio_exact(exact_match):
      """Test metric."""
      cp_true, cp_pred = exact_match
      assert prediction_ratio(cp_true, cp_pred) == 1.0
  
file_path: sktime/sktime/performance_metrics/tests/test_segmentation_metrics.py
imports: import pytest
  from sktime.performance_metrics.annotation.metrics import count_error, hausdorff_error, prediction_ratio
label_desc: Use image node_id 5 for calling a global function with example usage: test_prediction_ratio_exact(exact_match) without return types