class_docstr: YOLO V3 Detection Block which does the following:
  - add a few conv layers
  - return the output
  - have a branch that do yolo detection.
  Parameters
  ----------
  channel : int
      Number of channels for 1x1 conv. 3x3 Conv will have 2*channel.
  norm_layer : object
      Normalization layer used (default: :class:`mxnet.gluon.nn.BatchNorm`)
      Can be :class:`mxnet.gluon.nn.BatchNorm` or :class:`mxnet.gluon.contrib.nn.SyncBatchNorm`.
  norm_kwargs : dict
      Additional `norm_layer` arguments, for example `num_devices=4`
      for :class:`mxnet.gluon.contrib.nn.SyncBatchNorm`.
class_docstr_tok: ["YOLO","V3","Detection","Block","which","does","the","following",":","-","add","a","few","conv","layers","-","return","the","output","-","have","a","branch","that","do","yolo","detection",".","Parameters","--","--","--","--","--","channel",":","int","Number","of","channels","for","1x1","conv",".","3x3","Conv","will","have","2","*","channel",".","norm_layer",":","object","Normalization","layer","used","(","default",":",":","class",":","`","mxnet.gluon.nn.BatchNorm","`",")","Can","be",":","class",":","`","mxnet.gluon.nn.BatchNorm","`","or",":","class",":","`","mxnet.gluon.contrib.nn.SyncBatchNorm","`",".","norm_kwargs",":","dict","Additional","`","norm_layer","`","arguments",",","for","example","`","num_devices=4","`","for",":","class",":","`","mxnet.gluon.contrib.nn.SyncBatchNorm","`","."]
code: def hybrid_forward(self, F, x):
      route = self.body(x)
      tip = self.tip(route)
      return route, tip
  
imports: from __future__ import absolute_import
  from __future__ import division
  import os
  import warnings
  import numpy
  import mxnet
  from mxnet import gluon
  from mxnet import autograd
  from mxnet.gluon import nn
  from mxnet.gluon.nn import BatchNorm
  from .darknet import _conv2d, darknet53
  from ..mobilenet import get_mobilenet
  from .yolo_target import YOLOV3TargetMerger
  from ...loss import YOLOV3Loss
label_desc: Use image node_id 2 for calling the YOLODetectionBlockV3 obj's underlying member method code with example usage: obj.hybrid_forward(F, x) and returns: route,  tip