old_contents: # -*- coding: utf-8 -*-
  """
  Base HTTP client authentication classes.  These classes simply act as
  containers for authentication methods defined in the HTTP spec.
  """
  #import copy
  
  class AuthenticationCredentials(object):
      """
      A base class to represent authentication credentials.
      """
  #    @property
  #    def copy(self):
  #        return copy.deepcopy(self)
  
  
  class UserPasswordAuthenticationCredentials(AuthenticationCredentials):
      """
      A base class that represents username/password type authentication.
      """
      def __init__(self, username, password):
          self.username = username
          self.password = password
  
  
  class BasicAuthenticationCredentials(UserPasswordAuthenticationCredentials):
      """
      A class that represents Basic authentication.
      """
      pass
  
  
  class DigestAuthenticationCredentials(UserPasswordAuthenticationCredentials):
      """
      A class that represents Digest authentication.
      """
      pass
  
new_contents: # -*- coding: utf-8 -*-
  """
  Base HTTP client authentication classes.  These classes simply act as
  containers for authentication methods defined in the HTTP spec.
  """
  
  class AuthenticationCredentials(object):
      """
      A base class to represent authentication credentials.
      """
      pass
  
  
  class UserPasswordAuthenticationCredentials(AuthenticationCredentials):
      """
      A base class that represents username/password type authentication.
      """
      def __init__(self, username, password):
          self.username = username
          self.password = password
  
  
  class BasicAuthenticationCredentials(UserPasswordAuthenticationCredentials):
      """
      A class that represents Basic authentication.
      """
      pass
  
  
  class DigestAuthenticationCredentials(UserPasswordAuthenticationCredentials):
      """
      A class that represents Digest authentication.
      """
      pass
  
subject: Revert addition of copy operator