old_contents: 
  
  class ResponseCodes(object):
      SUCCESS = 0
  
      USER_CODE_START = 1
      USER_CODE_END = 0x7fffffff
  
      RESERVED_CODE_START = 0x80000000
      MALFORMED_RESPONSE = RESERVED_CODE_START
      REQUEST_ENCODING_FAILURE = RESERVED_CODE_START + 1
      REMOTE_UNHANDLED_EXCEPTION = RESERVED_CODE_START + 2
      CALL_REPLY_TIMEOUT = RESERVED_CODE_START + 3
      RESERVED_CODE_END = 0xffffffff
  
      _desc = {
          SUCCESS: 'Success',
          MALFORMED_RESPONSE: 'Response message was malformed',
          REQUEST_ENCODING_FAILURE: 'The data in the request could not be encoded',
          REMOTE_UNHANDLED_EXCEPTION: 'An unhandled exception occurred while processing the remote call',
          CALL_REPLY_TIMEOUT: 'The request did not receive a reply within the call timeout',
      }
  
      @staticmethod
      def describe(code):
          try:
              return ResponseCodes._desc[code]
          except KeyError:
              if ResponseCodes.USER_CODE_START >= code <= ResponseCodes.USER_CODE_END:
                  return 'RPC endpoint specific error response'
              else:
                  return 'Unknown response code'
  
  
  
new_contents: 
  
  class ResponseCodes(object):
      SUCCESS = 0
  
      USER_CODE_START = 1
      USER_CODE_END = 0x7fffffff
  
      RESERVED_CODE_START = 0x80000000
      MALFORMED_RESPONSE = RESERVED_CODE_START
      MALFORMED_REQUEST = RESERVED_CODE_START + 1
      REQUEST_ENCODING_FAILURE = RESERVED_CODE_START + 2
      REMOTE_UNHANDLED_EXCEPTION = RESERVED_CODE_START + 3
      CALL_REPLY_TIMEOUT = RESERVED_CODE_START + 4
      METHOD_NOT_FOUND = RESERVED_CODE_START + 5
      VERSION_NOT_FOUND = RESERVED_CODE_START + 6
      UNEXPECTED_DISPATCH_EXCEPTION = RESERVED_CODE_START + 7
  
      RESERVED_CODE_END = 0xffffffff
  
      _desc = {
          SUCCESS: 'Success',
          MALFORMED_RESPONSE: 'Response message was malformed',
          MALFORMED_REQUEST: 'Request message was malformed',
          REQUEST_ENCODING_FAILURE: 'The data in the request could not be encoded',
          REMOTE_UNHANDLED_EXCEPTION: 'An unhandled exception occurred while processing the remote call',
          CALL_REPLY_TIMEOUT: 'The request did not receive a reply within the call timeout',
          METHOD_NOT_FOUND: 'The requested method is not supported by the server',
          VERSION_NOT_FOUND: 'The requested method version is not supported by the server',
          UNEXPECTED_DISPATCH_EXCEPTION: 'An unexpected exception occurred during message dispatch'
      }
  
      @staticmethod
      def describe(code):
          try:
              return ResponseCodes._desc[code]
          except KeyError:
              if ResponseCodes.USER_CODE_START >= code <= ResponseCodes.USER_CODE_END:
                  return 'RPC endpoint specific error response'
              else:
                  return 'Unknown response code'
  
  
  
subject: Add additional codes used by server implementation