code: def forward(self, x):
      _, _, H, W = x.shape
      rpn_features = _random_array(
          self.xp, (1, 8, H // self.feat_stride, W // self.feat_stride)
      )
      roi_features = _random_array(
          self.xp, (1, 8, H // self.feat_stride, W // self.feat_stride)
      )
      return rpn_features, roi_features
  
imports: import numpy
  import unittest
  import chainer
  from chainer import testing
  from chainer.testing import attr
  from chainercv.experimental.links.model.fcis import FCIS
  from chainercv.utils import assert_is_instance_segmentation_link
  from chainercv.utils import generate_random_bbox
label_desc: Use image node_id 2 for calling the DummyExtractor obj's underlying member method code with example usage: obj.forward(x) and returns: rpn_features,  roi_features