class_docstr: A simple propositional knowledge base relying on compiled inference rules.
code: def __str__(self):
      return "{\n%s}" % ",\n".join(
          ["\t%s: %s" % i for i in sorted(self.items())]
      )
  
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 the FactKB obj's underlying member method code with example usage: obj.__str__() and returns: unknown