code: def _base_fact(atom):
      """Return the literal fact of an atom.
  
      Effectively, this merely strips the Not around a fact.
      """
      if isinstance(atom, Not):
          return atom.arg
      else:
          return atom
  
imports: from collections import defaultdict
  from typing import Iterator
  from .logic import Logic, And, Or, Not
label_desc: Use image node_id 1 for calling a global function with example usage: _base_fact(atom) and returns: atom, atom