Python UDP Socket Not Receiving Data -

i attempting write udp chat system, reason listen() loop not working , can not figure out why.

import socket                                                                                                                                 import json import landerdb import threading class peerchat:     def __init__(self):         self.sock = socket.socket(socket.af_inet, socket.sock_dgram)         self.db = landerdb.connect("nodes")         self.brok_ip = ""         self.brok_port = 5000      def listen(self):         while true:             msg = self.sock.recv(1024)             print msg      def main(self):         while true:             msg = raw_input("> ")             x in self.db.find("nodes", "all"):                 self.sock.sendto(msg, tuple(x['addr']))      def getnodes(self):         self.sock.sendto("as", (self.brok_ip, self.brok_port))         open("nodes", 'wb') file:             msg, addr = self.sock.recvfrom(1024)             print msg             file.write(msg)  if __name__ == "__main__":     peerchat().getnodes()     threading.thread(target=peerchat().listen).start()     peerchat().main()