docs: def to_bytes(self):
          '''
          Takes a list of ICMPv6Option objects and returns a packed byte string
          of options, appropriately padded if necessary.
          '''
          raw = b''
          if not self._options:
              return raw
          for icmpv6popt in self._options:
              raw += icmpv6popt.to_bytes()
          # Padding doesn't seem necessary?
          #   RFC states it should be padded to 'natural 64bit boundaries'
          #   However, wireshark interprets \x00 as a malformed option field
          #   So for now, ignore padding
          # padbytes = 4 - (len(raw) % 4)
          # raw += b'\x00'*padbytes
          return raw