class_docstr: Generic hierarchical cache for transformed functions.
  
  The keys are soft references (i.e. they are discarded when the key is
  destroyed) created from the source function by `_get_key`. The subkeys are
  strong references and can be any value. Typically they identify different
  kinds of transformation.
code: def __init__(self):
      self._cache = weakref.WeakKeyDictionary()
  
file_path: DALI/dali/python/nvidia/dali/_autograph/pyct/cache.py
imports: import inspect
  import weakref
label_desc: Use image node_id 1 to create a new _TransformedFnCache object from inherited base classes: object with example: obj = _TransformedFnCache()