Django 版本：3.0.8 - Python 版本：3.7.8我最近在 Django 網站上發(fā)現了一個錯誤。當用戶想要創(chuàng)建帳戶時，它會返回以下錯誤：序列項 0：預期的 str 實例，找到 NoneType手術：創(chuàng)建帳戶（檢查數據庫中是否尚不存在用戶名）創(chuàng)建用戶 Active = False發(fā)送一封電子郵件以確認帳戶創(chuàng)建。第一步出現錯誤，創(chuàng)建帳戶（Active = False），未發(fā)送電子郵件并顯示錯誤。Traceback (most recent call last):  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/core/handlers/exception.py", line 34, in inner    response = get_response(request)  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/core/handlers/base.py", line 115, in _get_response    response = self.process_exception_by_middleware(e, request)  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/core/handlers/base.py", line 113, in _get_response    response = wrapped_callback(request, *callback_args, **callback_kwargs)  File "/home/eodj89/DjangoPro/user/views.py", line 45, in signup    user.save()  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/contrib/auth/base_user.py", line 66, in save    super().save(*args, **kwargs)  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/db/models/base.py", line 746, in save    force_update=force_update, update_fields=update_fields)  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/db/models/base.py", line 795, in save_base    update_fields=update_fields, raw=raw, using=using,  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/dispatch/dispatcher.py", line 175, in send    for receiver in self._live_receivers(sender)  File "/home/eodj89/virtualenv/DjangoPro/3.7/lib/python3.7/site-packages/django/dispatch/dispatcher.py", line 175, in <listcomp>    for receiver in self._live_receivers(sender)  File "/home/eodj89/DjangoPro/user/models.py", line 479, in create_user_profile    UserProfile.objects.create(user=instance)