code: def test_cpu(self):
      self.check(self.x)
  
imports: import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links import FeaturePredictor
label_desc: Use image node_id 3 for calling the TestFeaturePredictorPredict obj's underlying member method code with example usage: obj.test_cpu() without return types