Initilize the CEMI frame with the given destination address.

def init_group(self, dst_addr=1):
        """Initilize the CEMI frame with the given destination address."""
        self.code = 0x11
        # frametype 1, repeat 1, system broadcast 1, priority 3, ack-req 0,
        # confirm-flag 0
        self.ctl1 = 0xbc
        self.ctl2 = 0xe0  # dst addr type 1, hop count 6, extended frame format
        self.src_addr = 0
        self.dst_addr = dst_addr