class_docstr: Base class for all Transformations.
  
  A Transformation processes works on a stream (iterator) of dictionaries.
class_docstr_tok: ["Base","class","for","all","Transformations",".","A","Transformation","processes","works","on","a","stream","(","iterator",")","of","dictionaries","."]
code: def apply(
      self, dataset: Dataset, is_train: bool = True
  ) -> "TransformedDataset":
      return TransformedDataset(dataset, self, is_train=is_train)
  
imports: import abc
  from dataclasses import dataclass
  from typing import Callable, Iterable, Iterator, List
  from gluonts.core.component import equals, validated
  from gluonts.dataset.common import DataEntry, Dataset
  from gluonts.env import env
label_desc: Use image node_id 4 for calling the Transformation obj's underlying member method code with example usage: obj.apply(dataset, is_train) and returns: TransformedDataset