code: def resize_imgs(self, targ, new_path, resume=True, fn=None):
          
          dest = resize_imgs(self.fnames, targ, self.path, new_path, resume, fn)
          return self.__class__(self.fnames, self.y, self.transform, dest)
docs: resize all images in the dataset and save them to `new_path`
          
          Arguments:
          targ (int): the target size
          new_path (string): the new folder to save the images
          resume (bool): if true (default), allow resuming a partial resize operation by checking for the existence
          of individual images rather than the existence of the directory
          fn (function): custom resizing function Img -> Img