class_docstr: Base class for all knowledge bases
class_docstr_tok: ["Base","class","for","all","knowledge","bases"]
code: def __init__(self, sentence=None):
      self.clauses_ = set()
      if sentence:
          self.tell(sentence)
  
imports: from sympy.logic.boolalg import And, Not, conjuncts, to_cnf, BooleanFunction
  from sympy.core.sorting import ordered
  from sympy.core.sympify import sympify
  from sympy.external.importtools import import_module
label_desc: Use image node_id 1 to create a new KB object  with example: obj = KB(sentence)