import webbrowser
url = 'http://www.stackoverflow.com'
url2 = 'http://www.stackexchange.com'

def main():
    webbrowser.open(url2) # To open new window
    print('Opening Stack Exchange website!')
    webbrowser.open_new_tab(url) # To open in new tab
    print('Opening Stack Overflow website in a new tab!')

if __name__ == '__main__':
    main()