class_docstr: Base class for Transformations that returns exactly one result per input in
  the stream.
class_docstr_tok: ["Base","class","for","Transformations","that","returns","exactly","one","result","per","input","in","the","stream","."]
code: def map_transform(self, data: DataEntry, is_train: bool) -> DataEntry:
      pass
  
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 2 for calling the MapTransformation obj's underlying member method code with example usage: obj.map_transform(data, is_train) without return types