text: #
  # This file contains the Python code from Program 4.16 of
  # "Data Structures and Algorithms
  # with Object-Oriented Design Patterns in Python"
  # by Bruno R. Preiss.
  #
  # Copyright (c) 2003 by Bruno R. Preiss, P.Eng.  All rights reserved.
  #
  # http://www.brpreiss.com/books/opus7/programs/pgm04_16.txt
  #
  class LinkedList(object):
  
      def prepend(self, item):
          tmp = self.Element(self, item, self._head)
          if self._head is None:
              self._tail = tmp
          self._head = tmp
  
      # ...
  