docstr: Test selecting specific flattened params
docstr_tok: ["Test","selecting","specific","flattened","params"]
code: def test_flattened_params(self, hspace):
      """Test selecting specific flattened params"""
      params = ["x[0]", "x[2]", "y[0,2]", "y[1,1]", "z"]
      assert flatten_params(hspace, params) == params
  
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 6 for calling the TestFlattenParams obj's underlying member method code with example usage: obj.test_flattened_params(hspace) without return types