code: def _conv3x3(channels, stride, in_channels):
      return nn.Conv2D(
          channels,
          kernel_size=3,
          strides=stride,
          padding=1,
          use_bias=False,
          in_channels=in_channels,
      )
  
imports: from __future__ import absolute_import
  import os
  import mxnet
  from mxnet import autograd
  from mxnet.gluon import nn
  from mxnet.gluon.contrib.nn import SyncBatchNorm
  from mxnet.gluon.nn import BatchNorm
  from mxnet.gluon.block import HybridBlock
  from .rcnn_target import RCNNTargetSampler, RCNNTargetGenerator
  from ..rcnn import custom_rcnn_fpn
  from ....model_zoo.rcnn import RCNN
  from ....model_zoo.rcnn.rpn import RPN
label_desc: Use image node_id 1 for calling a global function with example usage: _conv3x3(channels, stride, in_channels) and returns: nn