code: def test_log_rank_returns_None_if_equal_arrays():
      T = np.random.exponential(5, size=200)
      result = stats.logrank_test(T, T)
      assert result.p_value > 0.05
  
      C = np.random.binomial(1, 0.8, size=200)
      result = stats.logrank_test(T, T, C, C)
      assert result.p_value > 0.05
  
imports: import numpy
  import pandas
  import numpy.testing
  import pytest
  from pandas.testing import assert_frame_equal
  from lifelines import statistics
  from lifelines import CoxPHFitter, KaplanMeierFitter, WeibullFitter
  from lifelines.exceptions import StatisticalWarning
  from lifelines.datasets import load_waltons, load_g3, load_lymphoma, load_dd, load_regression_dataset, load_leukemia
label_desc: Use image node_id 24 for calling a global function with example usage: test_log_rank_returns_None_if_equal_arrays() without return types