class_docstr: Helper class used by nfa_to_dfa() to map back and forth between
  sets of states from the old machine and states of the new machine.
docstr: Given a new state, return a set of corresponding old states.
docstr_tok: ["Given","a","new","state",",","return","a","set","of","corresponding","old","states","."]
code: def new_to_old(self, new_state):
      """Given a new state, return a set of corresponding old states."""
      return self.new_to_old_dict[id(new_state)]
  
file_path: catboost/contrib/tools/cython/Cython/Plex/DFA.py
imports: from __future__ import absolute_import
  from .None import Machines
  from .Machines import LOWEST_PRIORITY
  from .Transitions import TransitionMap
label_desc: Use image node_id 4 for calling the StateMap obj's underlying member method code with example usage: obj.new_to_old(new_state) and returns: self