code: def forward(self, att_ws, ilens, olens):
      ga_masks = self._make_ga_masks(ilens, olens).to(att_ws.device)
      seq_masks = self._make_masks(ilens, olens).to(att_ws.device)
      losses = ga_masks * att_ws
      loss = torch.mean(losses.masked_select(seq_masks))
      return loss
  
imports: import math
  import numpy
  import torch
  from torch import nn
  from inspect import signature
  from torch.nn import functional
  from TTS.tts.utils.generic_utils import sequence_mask
  from TTS.tts.utils.ssim import ssim
label_desc: Use image node_id 3 for calling the GuidedAttentionLoss obj's underlying member method code with example usage: obj.forward(att_ws, ilens, olens) and returns: loss