Python 3 UDP multicast example, with only very minor modifications needed to this guidance: https://stackoverflow.com/a/1794373

multicast-rcv.py

# Multicast receiver
# Guidance:  https://stackoverflow.com/a/1794373
import socket
import struct

MCAST_GRP = '224.1.1.1'
MCAST_PORT = 5007
IS_ALL_GROUPS = True

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
if IS_ALL_GROUPS:
  # on this port, receives ALL multicast groups
  sock.bind(('', MCAST_PORT))
else:
  # on this port, listen ONLY to MCAST_GRP
  sock.bind((MCAST_GRP, MCAST_PORT))
mreq = struct.pack('4sl', socket.inet_aton(MCAST_GRP), socket.INADDR_ANY)

sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

while True:
  print(sock.recv(10240))

multicast-send.py

# Multicast sender
# Guidance:  https://stackoverflow.com/a/1794373
import socket

MCAST_GRP = '224.1.1.1'
MCAST_PORT = 5007
MESSAGE = b'Hello, Multicast!'

# regarding socket.IP_MULTICAST_TTL
# ---------------------------------
# for all packets sent, after two hops on the network the packet will not
# be re-sent/broadcast (see https://www.tldp.org/HOWTO/Multicast-HOWTO-6.html)
MULTICAST_TTL = 2

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, MULTICAST_TTL)

sock.sendto(MESSAGE, (MCAST_GRP, MCAST_PORT))