Django admin添加表单-当日期在范围内时，通过外键限制显示的型号数量

from django.db import models

class DateRange(models.Model):
    start_date = models.DateField()
    end_date = models.DateField()

class Model(models.Model):
    name = models.CharField(max_length=100)
    date_range = models.ForeignKey(DateRange, on_delete=models.CASCADE)

from django.contrib import admin
from .models import Model, DateRange

class ModelAdmin(admin.ModelAdmin):
    def formfield_for_foreignkey(self, db_field, request, **kwargs):
        if db_field.name == "date_range":
            # 获取当前日期
            current_date = datetime.date.today()
            # 获取日期范围在当前日期之内的所有日期范围对象
            date_ranges = DateRange.objects.filter(start_date__lte=current_date, end_date__gte=current_date)
            # 获取这些日期范围对象对应的型号数量
            model_counts = Model.objects.filter(date_range__in=date_ranges).values('date_range').annotate(count=models.Count('id'))
            # 获取型号数量小于等于10的日期范围对象
            valid_date_ranges = [date_range for date_range in date_ranges if model_counts.get(date_range=date_range.pk)['count'] <= 10]
            # 设置外键字段的查询集为有效的日期范围对象
            kwargs["queryset"] = DateRange.objects.filter(pk__in=[date_range.pk for date_range in valid_date_ranges])
        return super().formfield_for_foreignkey(db_field, request, **kwargs)

admin.site.register(Model, ModelAdmin)
admin.site.register(DateRange)