#!/usr/bin/python
# -*- coding: utf-8 -*-

import smtplib

msg = 'test'

server = smtplib.SMTP('mail.xyz.com',25)
server.ehlo()
server.login('test@xyz.com','123456')
server.set_debuglevel(1)
server.sendmail('test@xyz.com','test@xxx.com',msg)
server.close()

к примеру
msg1 = 'test1'
msg2 = 'test2'
msg3 = 'test3'
msg4 = 'test4'
msg5 = 'test5'

>>> import random
>>> lst = ['a', 'b', 'c', 'd', 'e']
>>> lstlen = len(lst)
>>> for i in range(lstlen):
...     v = lst[random.randint(0, lstlen - 1)]
...     print v
... 
d
b
e
a
c
>>> for i in range(lstlen):
...     v = lst[random.randint(0, lstlen - 1)]
...     print v
... 
e
a
d
e
e
>>>

from random import choise, seed

seed()
lst = ['a', 'b', 'c', 'd', 'e']
print(choise(lst))

import random

for i in range(1):
    msg = random.choice(['test1', 'test2', 'test3', 'test4', 'test5'])