code: def send_key(self, key):
          
          cmd = struct.pack(">BBBBBBH", 4, 1, 0, 0, 0, 0, key)
          self.con.send(cmd)
  
          cmd = struct.pack(">BBBBBBH", 4, 0, 0, 0, 0, 0, key)
          self.con.send(cmd)
docs: Send a key to the Horizon box.