new_contents: class IllegalFunctionError(Exception):
      """ The function code received in the request is not an allowable action for
      the server.
  
      """
      error_code = 1
  
      def __init__(self, function_code):
          self.function_code = function_code
  
      def __str__(self):
          return 'Function code \'{0}\' is not an allowable action for the ' + \
              'server.'.format(self.function_code)
  
  
  class IllegalDataAddressError(Exception):
      """ The data address received in de request is not an allowable address for
      the server.
  
      """
      error_code = 2
  
      def __str__(self):
          return self.__doc__
  
  
  class IllegalDataValueError(Exception):
      """ The value contained in the request data field is not an allowable value
      for the server.
  
      """
      error_code = 3
  
      def __str__(self):
          return self.__doc__
  
  
  class ServerDeviceFailureError(Exception):
      """ An unrecoverable error occurred. """
      error_code = 4
  
      def __str__(self):
          return 'An unrecoverable error occurred.'
  
  
  class AcknowledgeError(Exception):
      """ The server has accepted the requests and it processing it, but a long
      duration of time will be required to do so.
      """
      error_code = 5
  
      def __str__(self):
          return self.__doc__
  
  
  class ServerDeviceBusyError(Exception):
      """ The server is engaged in a long-duration program command. """
      error_code = 6
  
      def __str__(self):
          return self.__doc__
  
  
  class MemoryParityError(Exception):
      """ The server attempted to read record file, but detected a parity error
      in memory.
  
      """
      error_code = 8
  
      def __repr__(self):
          return self.__doc__
  
  
  class GatewayPathUnavailableError(Exception):
      """ The gateway is probably misconfigured or overloaded. """
      error_code = 11
  
      def __repr__(self):
          return self.__doc__
  
  
  class GatewayTargetDeviceFailedToRespondError(Exception):
      """ Didn't get a response from target device. """
      error_code = 12
  
      def __repr__(self):
          return self.__doc__
  
subject: Add exceptions module.