text: #
  # This file contains the Python code from Program 12.3 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/pgm12_03.txt
  #
  class SetAsArray(Set):
  
      def insert(self, item):
          self._array[item] = True
  
      def __contains__(self, item):
          return self._array[item]
  
      def withdraw(self, item):
          self._array[item] = False
  
      # ...
  