old_contents: import logging
  import warnings
  try:
      import cPickle as pickle
  except ImportError:
      import pickle
  
  logger = logging.getLogger(__name__)
  
  try:
      address_book = pickle.load(open('address_book.p', 'rb'))
  except IOError:
      logger.warning('Could not load address book!')
      warnings.warn('Could not load address book!')
      address_book = []
  
  
  def add_contact(name, email, fingerprint):
      address_book.append({'name': name, 'email': email, 'key': fingerprint})
      pickle.dump(address_book, open('address_book.p', 'wb'))
  
new_contents: import logging
  import warnings
  try:
      import cPickle as pickle
  except ImportError:
      import pickle
  
  logger = logging.getLogger(__name__)
  
  try:
      address_book = pickle.load(open('address_book.p', 'rb'))
  except IOError:
      logger.debug('Could not load address book!')
      warnings.warn('Could not load address book!')
      address_book = []
  
  
  def add_contact(name, email, fingerprint):
      address_book.append({'name': name, 'email': email, 'key': fingerprint})
      pickle.dump(address_book, open('address_book.p', 'wb'))
  
subject: Update for logging purposes