code: def check_call(self, x, expects):
      outs = self.link(x)
  
      if isinstance(self.pick, tuple):
          pick = self.pick
      else:
          if self.pick is None:
              pick = ("l2",)
          else:
              pick = (self.pick,)
          outs = (outs,)
  
      self.assertEqual(len(outs), len(pick))
  
      for out, layer_name in zip(outs, pick):
          self.assertIsInstance(out, chainer.Variable)
          self.assertIsInstance(out.array, self.link.xp.ndarray)
  
          out = to_cpu(out.array)
          np.testing.assert_equal(
              out, to_cpu(expects[layer_name].array)
          )
  
imports: import numpy
  import unittest
  import chainer
  from chainer.backends.cuda import to_cpu
  from chainer.function import Function
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links import PickableSequentialChain
  from chainercv.utils.testing import ConstantStubLink
label_desc: Use image node_id 5 for calling the PickableSequentialChainTestBase obj's underlying member method code with example usage: obj.check_call(x, expects) without return types