code: def test_StatisticalResult_can_be_added():
      sr1 = stats.StatisticalResult(
          0.01, 1.0, name=["1"], kw1="some_value1"
      )
      sr2 = stats.StatisticalResult(
          [0.02], [2.0], name=["2"], kw2="some_value2"
      )
      sr3 = stats.StatisticalResult(
          [0.03, 0.04], [3.3, 4.4], name=["3", "4"], kw3=3
      )
      sr = sr1 + sr2 + sr3
  
      assert sr.summary.shape[0] == 4
      assert sr.summary.index.tolist() == ["1", "2", "3", "4"]
      assert "kw3" in sr._kwargs
  
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 27 for calling a global function with example usage: test_StatisticalResult_can_be_added() without return types