class_docstr: Unit test class for an already-trained nearest neighbors classifier model,
  except predict and classify methods.
class_docstr_tok: ["Unit","test","class","for","an","already-trained","nearest","neighbors","classifier","model",",","except","predict","and","classify","methods","."]
docstr: Check the model _list_fields method.
docstr_tok: ["Check","the","model","_list_fields","method","."]
code: def test__list_fields(self):
      """
      Check the model _list_fields method.
      """
      correct_fields = [
          "distance",
          "num_distance_components",
          "verbose",
          "num_features",
          "training_time",
          "num_unpacked_features",
          "num_examples",
          "features",
          "target",
          "num_classes",
          "_target_type",
      ]
  
      self.assertItemsEqual(self.model._list_fields(), correct_fields)
  
imports: from __future__ import print_function
  from __future__ import division
  from __future__ import absolute_import
  import unittest
  import copy
  import array
  import numpy
  import turicreate
  from .None import util
  from turicreate.util import _assert_sframe_equal
  from turicreate.toolkits._main import ToolkitError
  import sys
label_desc: Use image node_id 2 for calling the KnnClassifierModelTest obj's underlying member method code with example usage: obj.test__list_fields() without return types