AttributeError：使用pip软件包安装软件包时，“ NoneType”对象没有属性“ encoding”

Question

我有一个使用bcrypt的程序，如果用户没有bcrypt，我想安装该软件包。它可以在我的PC上运行Python 3.7和最新版本的pip，但在学校时可以在标题中输入错误。这是相关代码：

try:
import bcrypt
except ImportError:
    from pip._internal import main as pip  # if bcrypt cannot be installed, attempt installation
    print("Attempting to install bcrypt...")
    pip(["install","bcrypt"])

这是错误：

Traceback (most recent call last):
  File "\\ths-fs-002\Student Work\2016\16HarveyJ\NEA-1\src\main.py", line 9, in <module>
    from pip._internal import main as pip  # if bcrypt cannot be installed, attempt installation
  File "C:\Python34\lib\site-packages\pip\__init__.py", line 9, in <module>
    from pip.log import logger
  File "C:\Python34\lib\site-packages\pip\log.py", line 8, in <module>
    from pip import backwardcompat
  File "C:\Python34\lib\site-packages\pip\backwardcompat\__init__.py", line 27, in <module>
    console_encoding = sys.__stdout__.encoding
AttributeError: 'NoneType' object has no attribute 'encoding'