code: def _activation_summary(x):
    
    # Remove 'tower_[0-9]/' from the name in case this is a multi-GPU training
    # session. This helps the clarity of presentation on tensorboard.
    tensor_name = re.sub('%s_[0-9]*/' % TOWER_NAME, '', x.op.name)
    tf.summary.histogram(tensor_name + '/activations', x)
    tf.summary.scalar(tensor_name + '/sparsity',
                                         tf.nn.zero_fraction(x))
docs: Helper to create summaries for activations.
  
    Creates a summary that provides a histogram of activations.
    Creates a summary that measures the sparsity of activations.
  
    Args:
      x: Tensor
    Returns:
      nothing