我正在做一个bug项目。它在Python 2.7上，我们正在迁移到Python 3.9。在manage.py导入from django.core.management import execute_from_command_line期间，我在www.example.com中收到导入错误。对于Python 2.7来说，它很好，但对于Python 3来说，它不起作用。我已经为Python 3创建了单独的虚拟环境。
manage.py

#!/usr/bin/env python
import os
import sys

if __name__ == "__main__":
    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "best_buy_mall.settings")
    try:
        from django.core.management import execute_from_command_line
    except ImportError:
        try:
            import django
        except ImportError:
            raise 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?"
            )
        raise
    execute_from_command_line(sys.argv)

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目录树：my_app/django_site/manage.py
my_app/venv（对于python 2）
my_app/v_env（对于python3）