class_docstr: Unit tests for the nearest neighbors builder class.
code: def setUp(self):
      iris_samples = load_iris()
      self.iris_X = iris_samples.data
      self.iris_y = iris_samples.target
      self.training_X = self.iris_X[-30:]
      self.training_y = self.iris_y[-30:]
  
imports: import os
  import shutil
  from coremltools.models.utils import _is_macos
  import unittest
  from coremltools.models import MLModel
  from coremltools.models.nearest_neighbors import KNearestNeighborsClassifierBuilder
  from coremltools._deps import _HAS_SKLEARN
label_desc: Use image node_id 1 for calling the NearestNeighborsBuilderTest obj's underlying member method code with example usage: obj.setUp() without return types