old_contents: from django.db.models.signals import post_save
  from django.dispatch import receiver
  
  from django.contrib.auth import get_user_model
  
  
  @receiver(post_save, sender=get_user_model())
  def post_save_user(sender, instance, created, **kwargs):
      if created:
          pass
  
new_contents: from django.db.models.signals import post_save
  from django.dispatch import receiver
  
  from django.contrib.auth import get_user_model
  
  import requests
  from time import sleep
  
  
  @receiver(post_save, sender=get_user_model())
  def post_save_user(sender, instance, created, **kwargs):
      if created:
          sleep(3)
  
          base_url = "http://api.openapi.io/ppurio/1/message/sms/dobestan"
          headers = {
              'x-waple-authorization': 'MTkyMC0xNDEzODU0NTAwMzU3LTllM2VkOTM3LTYwMTEtNGU2Zi1iZWQ5LTM3NjAxMTNlNmYyMg==',
          }
          data = {
                  "send_phone": "01029120007",
                  "dest_phone": "01029120007",
                  "msg_body": "새로운 회원가입",
          }
  
          response = requests.post(
              base_url,
              headers=headers,
              data=data,
          )
  
subject: update post_save_user: implement send_sms functionality