class_docstr: build a stub object for the NULL singleton
code: def __repr__(self):
      return "NULL"
  
file_path: klepto/klepto/_inspect.py
imports: import inspect
  from klepto.tools import IS_PYPY
  import sys
  from klepto.keymaps import keymap
  from klepto.rounding import simple_round, deep_round
  from copy import copy
label_desc: Use image node_id 1 for calling the _Null obj's underlying member method code with example usage: obj.__repr__() and returns: str