caused by a circular import.

class MenuModelForm(BootStrapModelForm):
    class Meta:
        model = models.Menu
        # django.core.exceptions.ImproperlyConfigured:
        # The included URLconf 'PHM.urls' does not appear to have any patterns in it.
        # If you see valid patterns in the file then the issue is probably caused by a circular import.
        # 哎呀我滴个天呀，不加这个fields一直报上面的错，一定一定要加，调了好久，报错还看不出来。。哎呀呀
        fields = ['title', 'icon']