IntegrityError：区分唯一约束和非空违规

I have this code:

我有这个代码:

try:
    principal = cls.objects.create(
        user_id=user.id,
        email=user.email,
        path='something'
    )
except IntegrityError:
    principal = cls.objects.get(
        user_id=user.id,
        email=user.email
    )
try:
    principa