code: def split_by_list(self, train, valid):
          "Split the data between `train` and `valid`."
          return self._split(self.path, train, validf split_by_list(self, train, valid):
          "Split the data between `train` and `valid`."
          return self._split(self.path, train, valid)
docs: Split the data between `train` and `valid`.