code: def _grad_op(self, out_grad):
      width = self._get_input_activation_vars().get_shape().as_list()[1]
      mask = tf.ones_like(self._get_input_activation_vars()) / float(
          width
      )
      return tf.multiply(tf.expand_dims(out_grad, axis=1), mask)
  
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 5 for calling the GlobalAvgPool1D obj's underlying member method code with example usage: obj._grad_op(out_grad) and returns: tf