tion should look something like this:   Copied def callback_dynamic_cfg(pipe, step_index, timestep, callback_kwargs):
        # adjust the batch_size of prompt_embeds according to guidance_scale
        if step_index == int(pipeline.num_timesteps * 0.4):
                prompt_embeds = callback_kwargs["prompt_embeds"]
                prompt_embeds = prompt_embeds.chunk(2)[-1]

                # update guidance_scale and prompt_embeds
          