从AbstractUser继承后，Django admin不能再更改用户的权限

from django.contrib import admin
from django.contrib.auth.admin import UserAdmin
from django.contrib.auth.models import Permission

from .models import CustomUser

class CustomUserAdmin(UserAdmin):
    model = CustomUser
    list_display = ('username', 'email', 'is_staff', 'is_active',)
    list_filter = ('is_staff', 'is_active',)
    fieldsets = (
        (None, {'fields': ('username', 'password')}),
        ('Personal Info', {'fields': ('email',)}),
        ('Permissions', {'fields': ('is_staff', 'is_active',)}),
    )
    add_fieldsets = (
        (None, {
            'classes': ('wide',),
            'fields': ('username', 'password1', 'password2', 'is_staff', 'is_active',),
        }),
    )
    search_fields = ('username', 'email',)
    ordering = ('username',)

admin.site.register(CustomUser, CustomUserAdmin)
admin.site.register(Permission)

AUTH_USER_MODEL = 'your_app.CustomUser'