getpass不起作用

#! /usr/bin/env python
# -*- coding:utf-8 -*-

# login 模块中登录时输入密码，想用getPass模块实现密码的不回显操作。
#如下：

import getpass
ret = input("welcome to the system:please make a choice-1 or 2")
if ret == '1':
    user = input("请输入用户名：")
    pwd = getpass.getpass("请输入密码：")

　　

#结果：
#在pycharm中根本不起作用，用官方带的IDLE显示如下：
    """
    welcome to the system:please make a choice-1 or 21
    请输入用户名：wuwuwu

    Warning (from warnings module):
      File "C:\Program Files\Python36\lib\getpass.py", line 100
        return fallback_getpass(prompt, stream)
    GetPassWarning: Can not control echo on the terminal.
    Warning: Password input may be echoed.
    请输入密码：123456
    用户名不存在
    >>> 
    """

# 命令行界面中测试可行，getpass模块只能用于命令行界面！
# stack overflow 上 有大神如是说：
"""
Use an actual terminal -- that is, an environment where stdin, 
stdout and stderr are connected to /dev/tty, or another PTY-compliant device.

The IDLE REPL does not meet this requirement.
"""