无法导入“pytz”模块

Question

我在PyCharm IDE中安装了pytz软件包，但是当我导入模块时，它会出错：

Traceback (most recent call last):
File "C:/Users/saika/PycharmProjects/Demo/Demo.py", line 2, in <module>     
import pytz
File "C:\Users\saika\PycharmProjects\Demo\venv\lib\site- 
packages\pytz\__init__.py", line 20, in <module>
from pytz.tzinfo import unpickler, BaseTzInfo
File "C:\Users\saika\PycharmProjects\Demo\venv\lib\site- 
packages\pytz\tzinfo.py", line 3, in <module>
from datetime import datetime, timedelta, tzinfo

  ImportError: cannot import name 'datetime'

我该怎么办？