code: def _db_pre_transform(self, train_tfm:List[Callable], valid_tfm:List[Callable]):
      "Call `train_tfm` and `valid_tfm` after opening image, before converting from `PIL.Image`"
      self.train_ds.x.after_open = compose(train_tfm)
      self.valid_ds.x.after_open = compose(valid_tfm)
      return self _db_pre_transform(self, train_tfm:List[Callable], valid_tfm:List[Callable]):
      "Call `train_tfm` and `valid_tfm` after opening image, before converting from `PIL.Image`"
      self.train_ds.x.after_open = compose(train_tfm)
      self.valid_ds.x.after_open = compose(valid_tfm)
      return self
docs: Call `train_tfm` and `valid_tfm` after opening image, before converting from `PIL.Image`