docstr: Saves attention alignments
docstr_tok: ["Saves","attention","alignments"]
code: def _save_attention_alignment(self):
      """Saves attention alignments"""
      attention = self.last_attn[0]
      if attention.dim() > 2:
          attention = attention[0]
      alignments_max = (
          attention.max(dim=-1)
          .values.max(dim=-1)
          .values.unsqueeze(-1)
          .unsqueeze(-1)
      )
      alignments_output = (
          attention.T.flip(dims=(1,)) / alignments_max
      ).unsqueeze(0)
      prefix = self.train_step["name"]
      self.tb_writer.add_image(
          f"valid/{prefix}_attention_alignments",
          alignments_output,
          self.tb_global_step,
      )
  
imports: from speechbrain.dataio.dataset import FilteredSortedDynamicItemDataset, DynamicItemDataset
  from speechbrain.dataio.sampler import BalancingDataSampler
  from speechbrain.utils.data_utils import undo_padding
  import datasets
  import logging
  import os
  import random
  import speechbrain
  import sys
  from enum import Enum
  from collections import namedtuple
  from hyperpyyaml import load_hyperpyyaml
  from functools import partial
  from speechbrain.utils.distributed import run_on_main
  from speechbrain.utils.pretrained import save_for_pretrained
  from speechbrain.lobes.models.g2p.dataio import enable_eos_bos, grapheme_pipeline, phoneme_pipeline, tokenizer_encode_pipeline, add_bos_eos, get_sequence_key, phonemes_to_label
  from speechbrain.dataio.wer import print_alignments
  from speechbrain.wordemb.util import expand_to_chars
  from io import StringIO
  from speechbrain.utils import hpopt
  import numpy
label_desc: Use image node_id 24 for calling the G2PBrain obj's underlying member method code with example usage: obj._save_attention_alignment() without return types