code: def before_batch(self):
      assert len(self.xb) == len(self.yb) == 1
  
      self.learn.records = self.yb[0]
      self.learn.yb = (self.xb[0][1],)
      self.learn.xb = (self.xb[0][0],)
  
file_path: icevision/icevision/models/fastai/unet/fastai.py
imports: from icevision.imports import *
  from icevision.engines.fastai import *
  from icevision.models.fastai.unet.prediction import convert_raw_predictions
label_desc: Use image node_id 1 for calling the UnetCallback obj's underlying member method code with example usage: obj.before_batch() without return types