          samples = [samples[0:num_images]] if samples is not None else [self.samples[0:num_images]]
          if self.use_mask:
              retval = [tgt[0:num_images] for tgt in images]
          else:
              retval = images[0:num_images]
          retval = samples + retval
          return retval
  
      def compile_timelapse_sample(self):
          """ Timelapse samples """
          batch = next(self.timelapse_feed)
 
</s> remove         samples = [samples[0:num_images]] if samples is not None else [self.samples[0:num_images]]
 </s> add         retval = [samples[0:num_images]] if samples is not None else [self.samples[0:num_images]] </s> remove             retval = [tgt[0:num_images] for tgt in images]
 </s> add             retval.extend(tgt[0:num_images] for tgt in images)
            retval.extend(images[0:num_images])
          samples = [samples[0:num_images]] if samples is not None else [self.samples[0:num_images]]
          if self.use_mask:
              retval = [tgt[0:num_images] for tgt in images]
          else:
            retval.extend(images[0:num_images])
            retval.extend(images[0:num_images])
          return retval
  
      def compile_timelapse_sample(self):
          """ Timelapse samples """
          batch = next(self.timelapse_feed)
keep keep keep keep replace replace keep keep keep keep keep
 trainer._base - explicit list extending for preview 
plugins/train/trainer/_base.py