python create system user and user group

#coding=utf8
import pwd
import grp
import sys
from _utils.patrol2 import run_cmd

info=None
try:
    info=pwd.getpwuid(uid)
except Exception as e:
    pass

if info:
    print 'uid already exists'
    sys.exit(1)

try:
    info=pwd.getpwnam(user)
except Exception as e:
    pass
if info:
    print 'User already exists'
    sys.exit(1)

try:
    info=grp.getgrgid(gid)
except Exception as e:
    pass

if info:
    print 'gid already exists'
    sys.exit(1)

try:
    info = grp.getgrnam(group)
except Exception as e:
    pass

if info:
    print 'group name already exists'
    sys.exit(1)

def run(cmd):
    code, res = run_cmd(cmd)
    if code:
        print res
        sys.exit(1)
        
try:
    run('groupadd -g {} {}'.format(gid,user))
    print 'Create user group successfully'
    
    run('useradd -u {} -d /var/mqm -g {} -m {}'.format(uid,group,user))
    print 'Create user and add user group successfully'

    run('echo "{}" |passwd --stdin {}'.format(password,user))
    print 'Modify user password successfully'
except Exception as e:
    print e
    sys.exit(1)