code: def _add_layer_summary(self, value, tag):
      tf.summary.scalar(
          "%s/fraction_of_zero_values" % tag, tf.nn.zero_fraction(value)
      )
      tf.summary.histogram("%s/activation" % tag, value)
  
imports: import time
  import argparse
  import tensorflow
  import os
  import sys
  import math
  import collections
  from tensorflow.python.client import timeline
  import json
  from tensorflow.python.ops import partitioned_variables
  import ray
  from bigdl.dllib.utils.log4Error import *
  from bigdl.orca import init_orca_context, stop_orca_context, OrcaContext
  from bigdl.orca.data.utils import process_spark_xshards
  from bigdl.orca.learn.utils import maybe_dataframe_to_xshards
  from bigdl.friesian.feature import FeatureTable
label_desc: Use image node_id 2 for calling the WDL obj's underlying member method code with example usage: obj._add_layer_summary(value, tag) without return types