code: def nodeid(self, iv, quantifier=False):
          
          return next(iter(self.nodeids(ivs=[iv], quantifier=quantifier)), None)
docs: Return the nodeid of the predication selected by *iv*.
  
          Args:
              iv: the intrinsic variable of the predication to select
              quantifier: if `True`, treat *iv* as a bound variable and
                  find its quantifier; otherwise the non-quantifier will
                  be returned