code: def test_z_score():
      s = pd.Series([0, 1, 2, 3, -1])
  
      m = s.mean()
      st = s.std()
  
      ans = (s - m) / st
  
      d = {}
  
      assert (s.z_score(moments_dict=d) == ans).all()
      assert (s.z_score().index == s.index).all()
  
      assert d["mean"] == m
      assert d["std"] == st
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_z_score() without return types