code: def addfield(self, pkt, s, val):
          
          if self.length_of(pkt) == 8:
              return s + struct.pack(self.fmt[0] + "B", val)
          if self.length_of(pkt) == 16:
              return s + struct.pack(self.fmt[0] + "H", val)
          if self.length_of(pkt) == 32:
              return s + struct.pack(self.fmt[0] + "2H", val)  # TODO: fix!
          if self.length_of(pkt) == 48:
              return s + struct.pack(self.fmt[0] + "3H", val)  # TODO: fix!
          elif self.length_of(pkt) == 64:
              return s + struct.pack(self.fmt[0] + "Q", val)
          elif self.length_of(pkt) == 128:
              # TODO: FIX THE PACKING!!
              return s + struct.pack(self.fmt[0] + "16s", raw(val))
          else:
              return s
docs: Add an internal value to a string