text: #! /usr/bin/env python
  # Copyright Ralf W. Grosse-Kunstleve 2006. Distributed under the Boost
  # Software License, Version 1.0. (See accompanying
  # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  
  # Using the doctest module here to ensure that the results are as expected.
  r'''>>> from extending import *
      >>> hi = hello('California')
      >>> hi.greet()
      'Hello from California'
      >>> invite(hi)
      'Hello from California! Please come soon!'
      >>> hi.invite()
      'Hello from California! Please come soon!'
  
      >>> class wordy(hello):
      ...     def greet(self):
      ...         return hello.greet(self) + ', where the weather is fine'
      ...
      >>> hi2 = wordy('Florida')
      >>> hi2.greet()
      'Hello from Florida, where the weather is fine'
      >>> invite(hi2)
      'Hello from Florida! Please come soon!'
  '''
  
  def run(args = None):
      if args is not None:
          import sys
          sys.argv = args
      import doctest, test_extending
      return doctest.testmod(test_extending, verbose=True)
  
  if __name__ == '__main__':
      import sys
      sys.exit(run()[0])
  
  