          logger.debug("Compiling samples: (side: '%s', samples: %s)", self.side, num_images)
          images = images if images is not None else self.target
          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
  
 
</s> remove             retval = images[0:num_images]
        retval = samples + retval
 </s> add             retval.extend(images[0:num_images]) </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]]
            retval.extend(tgt[0:num_images] for tgt in images)
          logger.debug("Compiling samples: (side: '%s', samples: %s)", self.side, num_images)
          images = images if images is not None else self.target
          samples = [samples[0:num_images]] if samples is not None else [self.samples[0:num_images]]
          if self.use_mask:
            retval.extend(tgt[0:num_images] for tgt in images)
          else:
              retval = images[0:num_images]
          retval = samples + retval
          return retval
  
keep keep keep keep replace keep keep keep keep keep
 trainer._base - explicit list extending for preview 
plugins/train/trainer/_base.py