code: def create_from_gbdt(cls, gbdt_model):
      jss = [json.loads(s) for s in gbdt_model._get("trees_json")]
      retval = GBDTDecoder()
      retval.combination_method = 0
      retval.tree_list = list(GBDTDecoder.parse_turicreate_json(jss))
      return retval
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import turicreate
  import unittest
  import json
  import random
  import numpy
  import pytest
label_desc: Use image node_id 5 for calling the GBDTDecoder obj's underlying member method code with example usage: obj.create_from_gbdt(cls, gbdt_model) and returns: retval