ftplib progress bar

问题

When I run the script it closes the terminal. I want to print and display a message and also to see that it has completed. Maybe a status bar?

import ftplib
from ftplib import FTP

ftp_add =  input('ftp address:')
username = input('username:')
password = input('password:')


ftp = FTP(ftp_add)
ftp.login(username, password)
ftp.retrlines('LIST')
ftp.cwd("/public_html")
file_list = []
filenames = ftp.nlst()


ftp.close() 

来源：https://stackoverflow.com/questions/43404660/ftplib-progress-bar