docstr: Trains the GAN with a batch
docstr_tok: ["Trains","the","GAN","with","a","batch"]
code: def fit_batch(self, batch):
      "Trains the GAN with a batch"
      self.g_optimizer.zero_grad()
      predictions = self.compute_forward(batch, sb.Stage.TRAIN)
      g_loss = self.compute_objectives(
          predictions, batch, sb.Stage.TRAIN, "generator"
      )
      g_loss.backward()
      self.g_optimizer.step()
  
      self.d_optimizer.zero_grad()
      predictions = self.compute_forward(batch, sb.Stage.TRAIN)
      d_loss = self.compute_objectives(
          predictions, batch, sb.Stage.TRAIN, "discriminator"
      )
      d_loss.backward()
      self.d_optimizer.step()
  
      return g_loss.detach() + d_loss.detach()
  
file_path: speechbrain/tests/integration/enhance_GAN/example_enhance_gan_experiment.py
imports: import torch
  import pathlib
  import speechbrain
  from hyperpyyaml import load_hyperpyyaml
label_desc: Use image node_id 3 for calling the EnhanceGanBrain obj's underlying member method code with example usage: obj.fit_batch(batch) and returns: unknown