old_contents: from django import forms
  
  
  class SubscribeForm(forms.Form):
      email = forms.EmailField()
      tags = forms.CharField()
  
      def clean_tags(self):
          tags = self.cleaned_data['tags'].split(',')
          return [t.strip().lower() for t in tags]
  
  
  class UnsubscribeForm(forms.Form):
      email = forms.EmailField()
  
new_contents: from django.contrib.auth.models import User
  from django import forms
  
  
  class SubscribeForm(forms.Form):
      email = forms.EmailField()
      tags = forms.CharField()
  
      def clean_tags(self):
          tags = self.cleaned_data['tags'].split(',')
          return [t.strip().lower() for t in tags]
  
  
  class UnsubscribeForm(forms.Form):
      email = forms.EmailField()
  
  
  class ConfirmForm(forms.Form):
      email = forms.EmailField()
      code = forms.CharField(max_length=80)
  
      def clean_email(self):
          email = self.cleaned_data['email']
          user = User.objects.filter(username=email).first()
          if not user:
              raise forms.ValidationError('Email not found')
          self.cleaned_data['user'] = user
          return email
  
subject: Add `ConfirmForm`