code: def setUp(self):
      feat_stride = 4
      C = 16
      H = 8
      W = 12
      self.proposal_creator_params = {
          "n_train_post_nms": 10,
          "n_test_post_nms": 5,
      }
      self.ratios = [0.25, 4]
      self.anchor_scales = [2, 4]
      self.link = RegionProposalNetwork(
          in_channels=C,
          mid_channels=24,
          ratios=self.ratios,
          anchor_scales=self.anchor_scales,
          feat_stride=feat_stride,
          proposal_creator_params=self.proposal_creator_params,
      )
      self.x = np.random.uniform(size=(self.B, C, H, W)).astype(
          np.float32
      )
      self.img_size = (H * feat_stride, W * feat_stride)
  
file_path: chainercv/tests/links_tests/model_tests/faster_rcnn_tests/test_region_proposal_network.py
imports: import numpy
  import unittest
  import chainer
  from chainer.backends import cuda
  from chainer import testing
  from chainer.testing import attr
  from chainercv.links.model.faster_rcnn import RegionProposalNetwork
label_desc: Use image node_id 1 for calling the TestRegionProposalNetwork obj's underlying member method code with example usage: obj.setUp() without return types