code: def test_concordance_index_returns_same_after_shifting():
      T = np.array([1, 2, 3, 4, 5, 6])
      T_ = np.array([2, 1, 4, 6, 5, 3])
      assert (
          concordance_index(T, T_)
          == concordance_index(T - 5, T_ - 5)
          == concordance_index(T, T_ - 5)
          == concordance_index(T - 5, T_)
      )
  
file_path: lifelines/lifelines/tests/utils/test_concordance.py
imports: import pytest
  import numpy
  import pandas
  from lifelines import CoxPHFitter
  from lifelines.datasets import load_rossi
  from lifelines.utils.concordance import concordance_index
  from lifelines.utils.concordance import concordance_index
  from lifelines.utils.concordance import naive_concordance_index
label_desc: Use image node_id 1 for calling a global function with example usage: test_concordance_index_returns_same_after_shifting() without return types