code: def _create_checkpoint(self, towers, trial_id):
      with self.test_session(graph=tf.Graph()) as sess:
          architecture = np.array([4])
          input_tensor = tf.zeros([100, 32, 32, 3])
          phoenix_spec = phoenix_spec_pb2.PhoenixSpec(
              problem_type=phoenix_spec_pb2.PhoenixSpec.CNN
          )
          dirname = os.path.join(flags.FLAGS.test_tmpdir, str(trial_id))
          if dirname and not tf.io.gfile.exists(dirname):
              tf.io.gfile.makedirs(dirname)
          for tower in towers:
              _ = architecture_utils.construct_tower(
                  phoenix_spec=phoenix_spec,
                  input_tensor=input_tensor,
                  tower_name=str(tower) + "_0",
                  architecture=architecture,
                  is_training=True,
                  lengths=None,
                  logits_dimension=10,
                  hparams=hp.HParams(),
                  model_directory=dirname,
                  is_frozen=False,
                  dropout_rate=None,
              )
              architecture_utils.set_number_of_towers(tower, 1)
          directory = flags.FLAGS.test_tmpdir
          saver = tf.compat.v1.train.Saver()
          sess.run(tf.compat.v1.global_variables_initializer())
          sess.run(tf.compat.v1.local_variables_initializer())
          saver.save(
              sess, os.path.join(directory, str(trial_id)) + "/ckpt"
          )
  
imports: import collections
  import os
  from absl import flags
  from model_search import hparam
  from model_search.architecture import architecture_utils
  from model_search.generators import search_candidate_generator
  from model_search.generators import trial_utils
  from model_search.metadata import ml_metadata_db
  from model_search.metadata import trial
  from model_search.proto import distillation_spec_pb2
  from model_search.proto import ensembling_spec_pb2
  from model_search.proto import phoenix_spec_pb2
  from model_search.proto import transfer_learning_spec_pb2
  import numpy
  import tensorflow.compat.v2
label_desc: Use image node_id 1 for calling the SearchCandidateGeneratorTest obj's underlying member method code with example usage: obj._create_checkpoint(towers, trial_id) without return types