docs: def to_bytes(self):
          '''
          Create bytes from properties
          '''
          # Verify that the properties make sense
          self.sanitize()
  
          # Write the version
          bitstream = BitStream('uint:4=%d' % self.version)
  
          # Write the traffic class
          bitstream += BitStream('uint:8=%d' % self.traffic_class)
  
          # Write the flow label
          bitstream += BitStream('uint:20=%d' % self.flow_label)
  
          # Write the payload length
          payload_bytes = bytes(self.payload)
          payload_length = len(payload_bytes)
          bitstream += BitStream('uint:16=%d' % payload_length)
  
          # Write the next header type
          bitstream += BitStream('uint:8=%d' % self.next_header)
  
          # Write the hop limit
          bitstream += BitStream('uint:8=%d' % self.hop_limit)
  
          # Write the source and destination addresses
          bitstream += BitStream('uint:128=%d, '
                                 'uint:128=%d' % (int(self.source),
                                                  int(self.destination)))
  
          return bitstream.bytes + payload_bytes