old_contents: # -*- encoding: utf-8 -*-
  from __future__ import unicode_literals
  
  from celery import shared_task
  
  from .service import send_mail
  
  
  @shared_task
  def process_mail():
      send_mail()
  
  
  @shared_task
  def process_periodic_task():
      send_mail()
  
new_contents: # -*- encoding: utf-8 -*-
  from __future__ import unicode_literals
  
  from celery import shared_task
  
  from .service import send_mail
  
  
  @shared_task
  def process_mail():
      send_mail()
  
subject: duplicate task