code: def testMergedLayout(self):
      ctx = context.RequestContext()
      parsed_layout = layout_pb2.Layout()
      json_format.Parse(
          self.plugin.layout_impl(ctx, "exp_id"), parsed_layout
      )
      correct_layout = layout_pb2.Layout(
          category=[
              # A category with this name is also present in a layout for a
              # different run (the logdir run)
              layout_pb2.Category(
                  title="cross entropy",
                  chart=[
                      layout_pb2.Chart(
                          title="cross entropy",
                          multiline=layout_pb2.MultilineChartContent(
                              tag=[r"cross entropy"],
                          ),
                      ),
                      layout_pb2.Chart(
                          title="cross entropy margin chart",
                          margin=layout_pb2.MarginChartContent(
                              series=[
                                  layout_pb2.MarginChartContent.Series(
                                      value="cross entropy",
                                      lower="cross entropy lower",
                                      upper="cross entropy upper",
                                  ),
                              ],
                          ),
                      ),
                  ],
                  closed=True,
              ),
              layout_pb2.Category(
                  title="mean biases",
                  chart=[
                      layout_pb2.Chart(
                          title="mean layer biases",
                          multiline=layout_pb2.MultilineChartContent(
                              tag=[
                                  r"mean/layer0/biases",
                                  r"mean/layer1/biases",
                              ],
                          ),
                      ),
                  ],
              ),
              layout_pb2.Category(
                  title="std weights",
                  chart=[
                      layout_pb2.Chart(
                          title="stddev layer weights",
                          multiline=layout_pb2.MultilineChartContent(
                              tag=[r"stddev/layer\d+/weights"],
                          ),
                      ),
                  ],
              ),
          ]
      )
      self.assertProtoEquals(correct_layout, parsed_layout)
  
imports: import csv
  import io
  import json
  import os
  import numpy
  import tensorflow
  from werkzeug import test
  from werkzeug import wrappers
  from google.protobuf import json_format
  from tensorboard.backend import application
  from tensorboard import context
  from tensorboard.backend.event_processing import data_provider
  from tensorboard.backend.event_processing import plugin_event_multiplexer
  from tensorboard.plugins import base_plugin
  from tensorboard.plugins.custom_scalar import custom_scalars_plugin
  from tensorboard.plugins.custom_scalar import layout_pb2
  from tensorboard.plugins.custom_scalar import summary
  from tensorboard.plugins.scalar import scalars_plugin
  from tensorboard.plugins.scalar import summary
  from tensorboard.util import test_util
label_desc: Use image node_id 6 for calling the CustomScalarsPluginTest obj's underlying member method code with example usage: obj.testMergedLayout() without return types