如何在Django中限制18岁以下用户的表单验证

from django import forms
from django.core.exceptions import ValidationError
from datetime import date

class AgeRestrictionForm(forms.Form):
    birth_date = forms.DateField(label='出生日期')

    def clean_birth_date(self):
        birth_date = self.cleaned_data['birth_date']
        today = date.today()
        age = today.year - birth_date.year - ((today.month, today.day) < (birth_date.month, birth_date.day))
        
        if age < 18:
            raise ValidationError("您必须年满18岁才能注册。")
        
        return birth_date

from django.shortcuts import render
from .forms import AgeRestrictionForm

def register(request):
    if request.method == 'POST':
        form = AgeRestrictionForm(request.POST)
        if form.is_valid():
            # 处理表单数据
            # ...
            return render(request, 'success.html')
    else:
        form = AgeRestrictionForm()
    
    return render(request, 'register.html', {'form': form})