code: def test_weighted_variance():
      x = np.array([1, 2, 3, 4, 5])
      sample_weight_equal = np.ones(len(x))
  
      var_x = get_weighted_variance(x, sample_weight_equal)
      # should get the same variance with equal sample_weight
      assert var_x == x.var()
  
      x1 = np.array([1, 2, 3, 4, 4, 5, 5])
      sample_weight_equal = np.ones(len(x1))
      sample_weight = [1, 1, 1, 2, 2]
      var_x2 = get_weighted_variance(x, sample_weight)
      var_x1 = get_weighted_variance(x1, sample_weight_equal)
  
      # should get the same variance by duplicate the observation based on the sample weight
      assert var_x1 == var_x2
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_weighted_variance() without return types