code: def transform_y(self, tfms:Optional[Tuple[TfmList,TfmList]]=(None,None), **kwargs):
          "Set `tfms` to be applied to the ys of the train and validation set."
          if not tfms: tfms=(None,None)
          self.train.transform_y(tfms[0], **kwargs)
          self.valid.transform_y(tfms[1], **kwargs)
          if self.test: self.test.transform_y(tfms[1], **kwargs)
          return self transform_y(self, tfms:Optional[Tuple[TfmList,TfmList]]=(None,None), **kwargs):
          "Set `tfms` to be applied to the ys of the train and validation set."
          if not tfms: tfms=(None,None)
          self.train.transform_y(tfms[0], **kwargs)
          self.valid.transform_y(tfms[1], **kwargs)
          if self.test: self.test.transform_y(tfms[1], **kwargs)
          return self
docs: Set `tfms` to be applied to the ys of the train and validation set.