docs: def iptag_set(self, iptag, addr, port, x, y):
          """Set the value of an IPTag.
  
          Forward SDP packets with the specified IP tag sent by a SpiNNaker
          application to a given external IP address.
  
          A :ref:`tutorial example <scp-and-sdp-tutorial>` of the use of IP Tags
          to send and receive SDP packets to and from applications is also
          available.
  
          Parameters
          ----------
          iptag : int
              Index of the IPTag to set
          addr : string
              IP address or hostname that the IPTag should point at.
          port : int
              UDP port that the IPTag should direct packets to.
          """
          # Format the IP address
          ip_addr = struct.pack('!4B',
                                *map(int, socket.gethostbyname(addr).split('.')))
          self._send_scp(x, y, 0, SCPCommands.iptag,
                         int(consts.IPTagCommands.set) << 16 | iptag,
                         port, struct.unpack('<I', ip_addr)[0])