docstr: test for json2space
          
docstr_tok: ["test","for","json2space"]
code: def test_json2space(self):
      """test for json2space"""
      json_search_space = {
          "optimizer": {"_type": "choice", "_value": ["Adam", "SGD"]},
          "learning_rate": {
              "_type": "choice",
              "_value": [0.0001, 0.001, 0.002, 0.005, 0.01],
          },
      }
      search_space_instance = json2space(json_search_space)
      self.assertIn("root[optimizer]-choice", search_space_instance)
      self.assertIn("root[learning_rate]-choice", search_space_instance)
  
imports: import numpy
  from unittest import TestCase, main
  from nni.utils import json2space, json2parameter
label_desc: Use image node_id 1 for calling the EvolutionTunerTestCase obj's underlying member method code with example usage: obj.test_json2space() without return types