code: def test_numpy_single_feat():
      ary = np.array([[1, 10], [2, 9], [3, 8], [4, 7], [5, 6], [6, 5]])
  
      ary_actu = standardize(ary, [1])
      ary_expc = np.array(
          [
              [1.46385],
              [0.87831],
              [0.29277],
              [-0.29277],
              [-0.87831],
              [-1.46385],
          ]
      )
  
      np.testing.assert_allclose(ary_actu, ary_expc, rtol=1e-03)
  
file_path: mlxtend/mlxtend/preprocessing/tests/test__scaling__standardizing.py
imports: import numpy
  import pandas
  from mlxtend.preprocessing import standardize
label_desc: Use image node_id 3 for calling a global function with example usage: test_numpy_single_feat() without return types