docstr: Tests the original dataframe is not modified
docstr_tok: ["Tests","the","original","dataframe","is","not","modified"]
code: def test_parameter_not_modified(self):
      """Tests the original dataframe is not modified"""
      data = pd.DataFrame(
          data={
              "order": ["a", "b", "c", "d"],
              "best": [0.1, 0.2, 0.3, 0.5],
          }
      )
  
      result = average(data)
  
      assert data.columns.tolist() == ["order", "best"]
      assert result.columns.tolist() == ["order", "best_mean"]
  
imports: import numpy
  import pandas
  import pytest
  from sklearn.ensemble import AdaBoostRegressor, BaggingRegressor, ExtraTreesRegressor, GradientBoostingRegressor, RandomForestRegressor
  from orion.analysis.base import average, flatten_numpy, flatten_params, ranking, to_numpy, train_regressor
  from orion.core.io.space_builder import SpaceBuilder
  from orion.core.worker.transformer import build_required_space
label_desc: Use image node_id 2 for calling the TestAverage obj's underlying member method code with example usage: obj.test_parameter_not_modified() without return types