code: def _create_bert_ckpt(self):
      config = encoders.EncoderConfig(
          type="bert", bert=encoders.BertEncoderConfig(num_layers=1)
      )
      encoder = encoders.build_encoder(config)
      ckpt = tf.train.Checkpoint(encoder=encoder)
      ckpt_path = ckpt.save(os.path.join(self._logging_dir, "ckpt"))
      return ckpt_path
  
imports: import os
  from absl import flags
  from absl.testing import parameterized
  import numpy
  import tensorflow
  from official.nlp.configs import encoders
  from tensorflow_ranking.extension.premade import tfrbert_task
  from tensorflow_ranking.python import data
  from tensorflow_ranking.python.keras import model
  from tensorflow_serving.apis import input_pb2
label_desc: Use image node_id 2 for calling the TFRBertTaskTest obj's underlying member method code with example usage: obj._create_bert_ckpt() and returns: ckpt_path