class_docstr: Use callable object instead of nested function, it can be pickled.
code: def __init__(self, fn):
      self._fn = fn
  
imports: import os
  from ...None import recordio, ndarray
  from ...util import default_array
label_desc: Use image node_id 1 to create a new _TransformFirstClosure object from inherited base classes: object with example: obj = _TransformFirstClosure(fn)