code: def _initialize_model(self, writer):
      HP_DENSE_NEURONS = hp.HParam(
          "dense_neurons", hp.IntInterval(4, 16)
      )
      self.hparams = {
          "optimizer": "adam",
          HP_DENSE_NEURONS: 8,
      }
      self.model = keras.models.Sequential(
          [
              keras.layers.Dense(
                  self.hparams[HP_DENSE_NEURONS], input_shape=(1,)
              ),
              keras.layers.Dense(1, activation="sigmoid"),
          ]
      )
      self.model.compile(
          loss="mse", optimizer=self.hparams["optimizer"]
      )
      self.trial_id = "my_trial"
      self.callback = _keras.Callback(
          writer, self.hparams, trial_id=self.trial_id
      )
  
file_path: tensorboard/tensorboard/plugins/hparams/_keras_test.py
imports: import os
  from unittest import mock
  from google.protobuf import text_format
  import tensorflow
  from tensorboard.plugins.hparams import _keras
  from tensorboard.plugins.hparams import metadata
  from tensorboard.plugins.hparams import plugin_data_pb2
  from tensorboard.plugins.hparams import summary_v2
label_desc: Use image node_id 2 for calling the CallbackTest obj's underlying member method code with example usage: obj._initialize_model(writer) without return types