A linked list is either:
#! /usr/bin/env python
class Node: 
      def __init__(self, cargo=None, next=None): 
          self.car = cargo 
          self.cdr = next    
      def __str__(self): 
          return str(self.car)
      def display(lst):
          if lst:
             w("%s " % lst)
             display(lst.cdr)
          else:
             w("nil\n")