code: def _check_call(self):
      x = self.link.xp.array(
          np.random.uniform(
              -1, 1, size=(1, 3, self.insize, self.insize)
          ),
          dtype=np.float32,
      )
  
      loc, conf = self.link(x)
  
      self.assertIsInstance(loc, chainer.Variable)
      self.assertIsInstance(loc.array, self.link.xp.ndarray)
      self.assertEqual(loc.shape, (1, self.n_bbox, 4))
      self.assertIsInstance(conf, chainer.Variable)
      self.assertIsInstance(conf.array, self.link.xp.ndarray)
      self.assertEqual(
          conf.shape, (1, self.n_bbox, self.n_fg_class + 1)
      )
  
file_path: chainercv/tests/links_tests/model_tests/ssd_tests/test_ssd_vgg16.py
imports: import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links import SSD300
  from chainercv.links import SSD512
label_desc: Use image node_id 2 for calling the TestSSDVGG16 obj's underlying member method code with example usage: obj._check_call() without return types