code: def test_prepare(self):
      img = np.random.randint(0, 255, size=(3, 480, 640))
      img = self.link._prepare(img)
      self.assertEqual(
          img.shape, (3, self.link.insize, self.link.insize)
      )
  
imports: import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links.model.ssd import Multibox
  from chainercv.links.model.ssd import SSD
  from chainercv.utils import assert_is_detection_link
label_desc: Use image node_id 5 for calling the TestSSD obj's underlying member method code with example usage: obj.test_prepare() without return types