code: def add_motif_stat(rl_tuner, action, stat_dict):
      """Updates stat dict if a motif was just played.
  
      Args:
        rl_tuner: An RLTuner object.
        action: One-hot encoding of the chosen action.
        stat_dict: A dictionary containing fields for statistics about
          compositions.
      Returns:
        A dictionary of composition statistics with 'notes_in_motif' field
        updated.
      """
      composition = rl_tuner.composition + [np.argmax(action)]
      motif, _ = rl_tuner.detect_last_motif(composition=composition)
      if motif is not None:
          stat_dict["notes_in_motif"] += 1
      return stat_dict
  
file_path: magenta/magenta/models/rl_tuner/rl_tuner_eval_metrics.py
imports: from magenta.models.rl_tuner import rl_tuner_ops
  import numpy
  import tensorflow.compat.v1
label_desc: Use image node_id 9 for calling a global function with example usage: add_motif_stat(rl_tuner, action, stat_dict) and returns: stat_dict