code: def test_wfg_duplicate_points() -> None:
      n = 3
      r = 10 * np.ones(n)
      s = [
          np.hstack((np.zeros(i), [1], np.zeros(n - i - 1)))
          for i in range(n)
      ]
      for _ in range(10):
          s.append(np.random.randint(1, 10, size=(n,)))
      o = np.asarray(s)
      v = optuna._hypervolume.WFG().compute(o, r)
  
      # Add an already existing point.
      o = np.vstack([o, o[-1]])
  
      np.random.shuffle(o)
      v_with_duplicate_point = optuna._hypervolume.WFG().compute(o, r)
      assert v == v_with_duplicate_point
  
file_path: optuna/tests/hypervolume_tests/test_wfg.py
imports: import numpy
  import pytest
  import optuna
label_desc: Use image node_id 4 for calling a global function with example usage: test_wfg_duplicate_points() without return types