已安装Django，但无法导入

Question

我已经安装了Django，但是无法执行manage.py

[root@iz2ze9wve43n2nyuvmsfx5z forum]# python manage.py shell
Traceback (most recent call last):
  File "manage.py", line 17, in <module>
    "Couldn't import Django. Are you sure it's installed and "
ImportError: Couldn't import Django. Are you sure it's installed and available on your PYTHONPATH environment variable? Did you forget to activate a virtual environment?

Django在那里存在

In [1]: import django
In [2]: django
Out[2]: <module 'django' from '/usr/local/lib/python3.6/site-packages/django/__init__.py'>
In [3]: django.__file__
Out[3]: '/usr/local/lib/python3.6/site-packages/django/__init__.py'