code: def check_prepare(self):
      x = _random_array(np, self.in_shape)
      out = self.link.prepare(x)
      self.assertIsInstance(out, np.ndarray)
      self.assertEqual(out.shape, self.expected_shape)
  
imports: import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links.model.light_head_rcnn import LightHeadRCNN
  from chainercv.utils import assert_is_detection_link
  from chainercv.utils import generate_random_bbox
label_desc: Use image node_id 2 for calling the TestLightHeadRCNNPrepare obj's underlying member method code with example usage: obj.check_prepare() without return types