def METHOD_NAME(url_base, file_name):
    if not os.path.exists(file_name) or not os.path.isfile(file_name):
        import urllib.request as urllib2
        url = "{}/{}".format(url_base, file_name)
        try:
            print("download from {}".format(url))
            if sys.version_info >= (3,):
                urllib2.urlretrieve(url, file_name)
            else:
                f = urllib2.urlopen(url)
                data = f.read()
                with open(file_name, "wb") as code:
                    code.write(data)
        except Exception as err:
            if os.path.exists(file_name):
                os.remove(file_name)
            raise Exception("download {} failed due to {}!".format(file_name, repr(err)))