code: def __set_revlookup_auth_string(self, username, password):
          '''
          Creates and sets the authentication string for accessing the reverse
              lookup servlet. No return, the string is set as an attribute to
              the client instance.
  
          :param username: Username.
          :param password: Password.
          '''
          auth = b2handle.utilhandle.create_authentication_string(username, password)
          self.__revlookup_auth_string = autf __set_revlookup_auth_string(self, username, password):
          '''
          Creates and sets the authentication string for accessing the reverse
              lookup servlet. No return, the string is set as an attribute to
              the client instance.
  
          :param username: Username.
          :param password: Password.
          '''
          auth = b2handle.utilhandle.create_authentication_string(username, password)
          self.__revlookup_auth_string = auth
docs: Creates and sets the authentication string for accessing the reverse
              lookup servlet. No return, the string is set as an attribute to
              the client instance.
  
          :param username: Username.
          :param password: Password.