code: def get_default_hparams():
      """Returns the default hyperparameters.
  
      Returns:
        A tf.contrib.training.HParams object representing the default
        hyperparameters for the model.
      """
      return contrib_training.HParams(
          batch_size=8,
          learning_rate=0.0006,
          decay_steps=10000,
          decay_rate=0.98,
          clip_norm=3.0,
          transform_audio=False,
          max_expected_train_example_len=625,  # 20 seconds
          offset_network=True,
          onset_lstm_units=256,
          offset_lstm_units=256,
          velocity_lstm_units=0,
          frame_lstm_units=0,
          combined_lstm_units=256,
          bidirectional=True,
          acoustic_rnn_stack_size=1,
          acoustic_rnn_dropout_keep_prob=1.0,
          combined_rnn_stack_size=1,
          combined_rnn_dropout_keep_prob=1.0,
          activation_loss=False,
          stop_activation_gradient=False,
          stop_onset_gradient=True,
          stop_offset_gradient=True,
          weight_frame_and_activation_loss=False,
          share_conv_features=False,
          temporal_sizes=[3, 3, 3],
          freq_sizes=[3, 3, 3],
          num_filters=[48, 48, 96],
          pool_sizes=[1, 2, 2],
          dropout_keep_amts=[1.0, 0.25, 0.25],
          fc_size=768,
          fc_dropout_keep_amt=0.5,
          use_tflite_compatible=False,
          use_lengths=False,
          predict_frame_threshold=0.5,
          predict_onset_threshold=0.5,
          predict_offset_threshold=0,
      )
  
file_path: magenta/magenta/models/onsets_frames_transcription/model_tpu.py
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  from magenta.contrib import rnn
  from magenta.contrib import training
  from magenta.models.onsets_frames_transcription import constants
  from magenta.models.onsets_frames_transcription import estimator_spec_util
  import tensorflow.compat.v1
  from tensorflow.compat.v1 import estimator
  import tf_slim
label_desc: Use image node_id 7 for calling a global function with example usage: get_default_hparams() and returns: contrib_training