问防止用户在多台计算机上使用该程序。

EN

from uuid import getnode as get_mac
import os

def welcome():
    print('welcome user!')

purchased = false; # this will be declared true after payment.

if ((not os.path.exists('devId')) and purchased):
    # activation after payment
    open('devId', 'wt').write(str(get_mac()));
    welcome();
elif (open('devId', 'rt').read() == get_mac()):
    print('Purchase before using!')
    exit()
else:
    welcome();