code: def on_train_batch_start(self, batch, batch_idx, unused=0):
      if self.is_module_updatable(self.guidance):
          self.guidance.update_step(
              epoch=self.current_epoch, global_step=self.global_step
          )
  
      if self.is_module_updatable(self.renderer.nerf):
          self.renderer.nerf.update_step(
              epoch=self.current_epoch, global_step=self.global_step
          )
  
      if self.is_module_updatable(self.renderer.material):
          self.renderer.material.update_step(
              epoch=self.current_epoch, global_step=self.global_step
          )
  
      if self.is_module_updatable(self.renderer.background):
          self.renderer.background.update_step(
              epoch=self.current_epoch, global_step=self.global_step
          )
  
      if self.is_module_updatable(self.renderer):
          self.renderer.update_step(
              epoch=self.current_epoch, global_step=self.global_step
          )
  
      dataset = self.trainer.train_dataloader.dataset
      if self.is_module_updatable(dataset):
          dataset.update_step(
              epoch=self.current_epoch, global_step=self.global_step
          )
  
file_path: NeMo/nemo/collections/multimodal/models/nerf/txt2nerf_base.py
imports: from nemo.collections.multimodal.models.nerf.base import NerfModelBase
label_desc: Use image node_id 6 for calling the Txt2NerfBase obj's underlying member method code with example usage: obj.on_train_batch_start(batch, batch_idx, unused) without return types