Update the self.x_bounds and self.x_types by the search_space.json

        Parameters
        ----------
        search_space : dict

def update_search_space(self, search_space):
        """Update the self.x_bounds and self.x_types by the search_space.json

        Parameters
        ----------
        search_space : dict
        """
        self.x_bounds = [[] for i in range(len(search_space))]
        self.x_types = [NONE_TYPE for i in range(len(search_space))]

        for key in search_space:
            self.key_order.append(key)

        key_type = {}
        if isinstance(search_space, dict):
            for key in search_space:
                key_type = search_space[key]['_type']
                key_range = search_space[key]['_value']
                idx = self.key_order.index(key)
                if key_type == 'quniform':
                    if key_range[2] == 1:
                        self.x_bounds[idx] = [key_range[0], key_range[1]]
                        self.x_types[idx] = 'range_int'
                    else:
                        bounds = []
                        for value in np.arange(key_range[0], key_range[1], key_range[2]):
                            bounds.append(value)
                        self.x_bounds[idx] = bounds
                        self.x_types[idx] = 'discrete_int'
                elif key_type == 'randint':
                    self.x_bounds[idx] = [0, key_range[0]]
                    self.x_types[idx] = 'range_int'
                elif key_type == 'uniform':
                    self.x_bounds[idx] = [key_range[0], key_range[1]]
                    self.x_types[idx] = 'range_continuous'
                elif key_type == 'choice':
                    self.x_bounds[idx] = key_range

                    for key_value in key_range:
                        if not isinstance(key_value, (int, float)):
                            raise RuntimeError("Metis Tuner only support numerical choice.")

                    self.x_types[idx] = 'discrete_int'
                else:
                    logger.info("Metis Tuner doesn't support this kind of variable: " + str(key_type))
                    raise RuntimeError("Metis Tuner doesn't support this kind of variable: " + str(key_type))
        else:
            logger.info("The format of search space is not a dict.")
            raise RuntimeError("The format of search space is not a dict.")

        self.minimize_starting_points = _rand_init(self.x_bounds, self.x_types, \
                                                        self.selection_num_starting_points)