#NEWLINE# def __init__( self , message_type , fields , description = '' ) : #NEWLINE# #INDENT# '\n        @ivar type: The name of the type,\n            e.g. C{"yourapp:subsystem:yourtype"}.\n\n        @ivar fields: A C{list} of L{Field} instances which can appear in this\n            type.\n\n        @param description: A description of what this message means.\n        @type description: C{unicode}\n        ' #NEWLINE# self . message_type = message_type #NEWLINE# self . description = description #NEWLINE# self . _serializer = _MessageSerializer ( ( fields + [ Field . forValue ( MESSAGE_TYPE_FIELD , message_type , 'The message type.' ) ] ) )