code: def __init__(self, fn: Callable) -> None:
      self.fn = fn
  
imports: from typing import Callable, Iterator, List, Optional, Tuple, Type
  import numpy
  from toolz import valmap
  from gluonts.core.component import validated, tensor_to_numpy
  from gluonts.dataset.common import DataEntry
  from gluonts.exceptions import assert_data_error
  from ._base import FlatMapTransformation, MapTransformation, SimpleTransformation
label_desc: Use image node_id 1 to create a new Valmap object from inherited base classes: SimpleTransformation with example: obj = Valmap(fn)