code: def _build_activation_vars(self, input_act_vars):
      return tf.reduce_mean(input_act_vars, axis=1)
  
imports: from __future__ import division
  from __future__ import print_function
  from __future__ import absolute_import
  from .core import *
  from .helper_functions import conv1d_transpose_via_conv2d
  from .convolutional import PaddingMode, DataFormat
  from .None import helper_functions
  import tensorflow
  from tensorflow.python.ops import nn_grad
label_desc: Use image node_id 3 for calling the GlobalAvgPool1D obj's underlying member method code with example usage: obj._build_activation_vars(input_act_vars) and returns: tf