code: def test_summary_str(self):
      for model in self.models:
          self.assertTrue(isinstance(model.summary("str"), str))
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import os
  import turicreate
  from turicreate.toolkits._main import ToolkitError
  import numpy
  import tempfile
  from array import array
  import sys
  from .None import util
  import unittest
label_desc: Use image node_id 31 for calling the DrawingClassifierTest obj's underlying member method code with example usage: obj.test_summary_str() without return types