(self, extended_message)
extended_message: Message instance for which we are the Extensions dict.
extended_message: Message instance for which we are the Extensions dict.
extended_message : Message instance for which we are the Extensions dict .
def __init__(self, extended_message):
    """extended_message: Message instance for which we are the Extensions dict.
    """

    self._extended_message = extended_message
def __init__ ( self , extended_message ) : self . _extended_message = extended_message