

def notify_topic_subscribers(post):
    topic = post.topic
    if (post != topic.head):
        old_lang = translation.get_language()
        delete_url = reverse('pybb:delete_subscription', args=[post.topic.id])
        current_site = Site.objects.get_current()
        from_email = settings.DEFAULT_FROM_EMAIL
        subject = render_to_string('pybb/mail_templates/subscription_email_subject.html', {
            'site': current_site,
            'post': post,
        })
        subject = ''.join(subject.splitlines())
        mails = tuple()
        for user in topic.subscribers.exclude(pk=post.user.pk):
            try:
                validate_email(user.email)
            except:
                continue
            if (user.email == ('%s@example.com' % getattr(user, compat.get_username_field()))):
                continue
            lang = (util.get_pybb_profile(user).language or settings.LANGUAGE_CODE)
            translation.activate(lang)
            message = render_to_string('pybb/mail_templates/subscription_email_body.html', {
                'site': current_site,
                'post': post,
                'delete_url': delete_url,
                'user': user,
            })
            mails += ((subject, from_email, from_email, [user.email]),)
        send_mass_mail(mails, fail_silently=True)
        translation.activate(old_lang)

dataset/ETHPy150Open hovel/pybbm/pybb/subscription.py notify_topic_subscribers/VarMisuse@235/333 `message`->`from_email`