code: def handle_initialize(self, data):
          
          logger.info('start to handle_initialize')
          # convert search space jason to ConfigSpace
          self.handle_update_search_space(data)
  
          # generate BOHB config_generator using Bayesian optimization
          if self.search_space:
              self.cg = CG_BOHB(configspace=self.search_space,
                                min_points_in_model=self.min_points_in_model,
                                top_n_percent=self.top_n_percent,
                                num_samples=self.num_samples,
                                random_fraction=self.random_fraction,
                                bandwidth_factor=self.bandwidth_factor,
                                min_bandwidth=self.min_bandwidth)
          else:
              raise ValueError('Error: Search space is None')
          # generate first brackets
          self.generate_new_bracket()
          send(CommandType.Initialized, '')
docs: Initialize Tuner, including creating Bayesian optimization-based parametric models 
          and search space formations
  
          Parameters
          ----------
          data: search space
              search space of this experiment
  
          Raises
          ------
          ValueError
              Error: Search space is None