code: def test_recursive_dict_to_flat(separator):
      dict_values = {"hp": 1, "stepa": {"hp": 2, "stepb": {"hp": 3}}}
      r = RecursiveDict(separator=separator, **dict_values)
  
      r = r.to_flat_dict()
  
      expected_dict_values = {
          "hp": 1,
          "stepa{}hp".format(separator): 2,
          "stepa{0}stepb{0}hp".format(separator): 3,
      }
      assert r == expected_dict_values
  
file_path: Neuraxle/testing_neuraxle/test_recursive_dict.py
imports: import pytest
  from neuraxle.hyperparams.space import RecursiveDict, HyperparameterSamples
label_desc: Use image node_id 1 for calling a global function with example usage: test_recursive_dict_to_flat(separator) without return types