class_docstr: ResNet101 Extractor for FCIS ResNet101 implementation.
  
  This class is used as an extractor for FCISResNet101.
  This outputs feature maps.
  Dilated convolution is used in the C5 stage.
  
  Args:
      initialW: Initializer for ResNet101 extractor.
class_docstr_tok: ["ResNet101","Extractor","for","FCIS","ResNet101","implementation",".","This","class","is","used","as","an","extractor","for","FCISResNet101",".","This","outputs","feature","maps",".","Dilated","convolution","is","used","in","the","C5","stage",".","Args",":","initialW",":","Initializer","for","ResNet101","extractor","."]
code: def __init__(self, initialW=None):
      super(ResNet101Extractor, self).__init__()
  
      if initialW is None:
          initialW = chainer.initializers.HeNormal()
      kwargs = {
          "initialW": initialW,
          "bn_kwargs": {"eps": 1e-5},
          "stride_first": True,
      }
  
      with self.init_scope():
          # ResNet
          self.conv1 = Conv2DBNActiv(
              3, 64, 7, 2, 3, nobias=True, initialW=initialW
          )
          self.pool1 = lambda x: F.max_pooling_2d(x, ksize=3, stride=2)
          self.res2 = ResBlock(3, 64, 64, 256, 1, **kwargs)
          self.res3 = ResBlock(4, 256, 128, 512, 2, **kwargs)
          self.res4 = ResBlock(23, 512, 256, 1024, 2, **kwargs)
          self.res5 = ResBlock(3, 1024, 512, 2048, 1, 2, **kwargs)
  
imports: from __future__ import division
  import chainer
  import chainer.functions
  import chainer.links
  import numpy
  from chainercv.experimental.links.model.fcis import FCIS
  from chainercv.functions import ps_roi_average_pooling_2d
  from chainercv.links import Conv2DBNActiv
  from chainercv.links.model.faster_rcnn.region_proposal_network import RegionProposalNetwork
  from chainercv.links.model.faster_rcnn.utils.loc2bbox import loc2bbox
  from chainercv.links.model.resnet.resblock import ResBlock
  from chainercv.links import ResNet101
  from chainercv import utils
label_desc: Use image node_id 1 to create a new ResNet101Extractor object from inherited base classes: chainer with example: obj = ResNet101Extractor(initialW)