def __init__(self, dh_pub, n, pn):
        """
        Initiate a message header.

        :param dh_pub: A bytes-like object encoding the new public key of the senders
            diffie-hellman ratchet.
        :param n: The current length of the senders sending chain, as an integer.
        :param pn: The length of the senders previous sending chain, as an integer. This
            enables the receiver to store keys for skipped messages of the previous chain.
        """

        self.__dh_pub = dh_pub
        self.__n  = n
        self.__pn = pn
def __init__ ( self , dh_pub , n , pn ) : self . __dh_pub = dh_pub self . __n = n self . __pn = pn
Initiate a message header.

        :param dh_pub: A bytes-like object encoding the new public key of the senders
            diffie-hellman ratchet.
        :param n: The current length of the senders sending chain, as an integer.
        :param pn: The length of the senders previous sending chain, as an integer. This
            enables the receiver to store keys for skipped messages of the previous chain.