code: def _make_transition(num_output_features):
      out = nn.HybridSequential(prefix="")
      out.add(nn.BatchNorm())
      # out.add(nn.Activation('relu'))
      out.add(Act())
      out.add(
          nn.Conv2D(num_output_features, kernel_size=1, use_bias=False)
      )
      out.add(nn.AvgPool2D(pool_size=2, strides=2))
      return out
  
file_path: insightface/recognition/arcface_mxnet/symbol/fdensenet.py
imports: import sys
  import os
  import mxnet
  import mxnet.ndarray
  import mxnet.gluon
  import mxnet.gluon.nn
  import mxnet.autograd
  import symbol_utils
  from config import config
label_desc: Use image node_id 4 for calling a global function with example usage: _make_transition(num_output_features) and returns: out