code: def _serialized_plugin_data(self, data_oneof_field, text_protobuffer):
      oneof_type_dict = {
          DATA_TYPE_EXPERIMENT: api_pb2.Experiment,
          DATA_TYPE_SESSION_START_INFO: plugin_data_pb2.SessionStartInfo,
          DATA_TYPE_SESSION_END_INFO: plugin_data_pb2.SessionEndInfo,
      }
      protobuffer = text_format.Merge(
          text_protobuffer, oneof_type_dict[data_oneof_field]()
      )
      plugin_data = plugin_data_pb2.HParamsPluginData()
      getattr(plugin_data, data_oneof_field).CopyFrom(protobuffer)
      return metadata.create_summary_metadata(
          plugin_data
      ).plugin_data.content
  
imports: import operator
  from unittest import mock
  import tensorflow
  from google.protobuf import text_format
  from tensorboard import context
  from tensorboard.data import provider
  from tensorboard.plugins import base_plugin
  from tensorboard.plugins.hparams import api_pb2
  from tensorboard.plugins.hparams import backend_context
  from tensorboard.plugins.hparams import metadata
  from tensorboard.plugins.hparams import plugin_data_pb2
label_desc: Use image node_id 32 for calling the BackendContextTest obj's underlying member method code with example usage: obj._serialized_plugin_data(data_oneof_field, text_protobuffer) and returns: metadata