我有一个从AbstractUser继承的customerUser，如果用户注册电子邮件aaaa@gmail.com，然后第二次，他试图注册与谷歌登录和相同的电子邮件（aaa@gmail.com）
Django-Alluth是否创建了一个重复的用户，如果是的话，我该如何避免这种情况？

from django.contrib.auth.forms import UserCreationForm, UserChangeForm
from .models import CustomUser

class CustomUserCreationForm(UserCreationForm):
    class Meta(UserCreationForm.Meta):
        model = CustomUser
        fields = (
            "username",
            "email",
            "age",
        )  # ne
        email = {"required": True}

class CustomUserChangeForm(UserChangeForm):
    class Meta:
        model = CustomUser
        fields = (
            "username",
            "email",
            "age",
        )  # ne
        email = {"required": True}

class CustomUser(AbstractUser):
    age = models.PositiveIntegerField(null=True, blank=True)
    email = models.EmailField(blank=False, null=False)

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