code: def init_group(self, dst_addr=1):
          
          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
docs: Initilize the CEMI frame with the given destination address.