code: def do_email_reply(self, comment, entry, site):
          
          if not self.email_reply:
              return
  
          exclude_list = (
              self.mail_comment_notification_recipients
              + [author.email for author in entry.authors.all()]
              + [comment.email]
          )
          recipient_list = (
              set([other_comment.email
                   for other_comment in entry.comments
                   if other_comment.email])
              - set(exclude_list)
          )
          if not recipient_list:
              return
  
          template = loader.get_template(
              'comments/zinnia/entry/email/reply.txt')
          context = {
              'comment': comment,
              'entry': entry,
              'site': site,
              'protocol': PROTOCOL
          }
          subject = _('[%(site)s] New comment posted on "%(title)s"') % \
              {'site': site.name, 'title': entry.title}
          message = template.render(context)
  
          mail = EmailMessage(
              subject, message,
              settings.DEFAULT_FROM_EMAIL,
              bcc=recipient_list)
          mail.send(fail_silently=not settings.DEBUG)
docs: Send email notification of a new comment to
          the authors of the previous comments.