title: How to access request parameters from SET value of on_delete in django model
body: <p>I have about 10 models each of which use User as a Foreign Key.  When the user is deleted, I want to set the values in each of these tables to the one who deletes the user. The users are being deleted through django admin area by authorized staff.</p>
  
  <p>So, I guess I have to call a function and use SET of on_delete method to set the value.
  This is the code as per documentation.</p>
  
  <pre><code>from django.db import models
  from django.contrib.auth.models import User
  
  def get_sentinel_user():
      return User.objects.get_or_create(username='deleted')[0]
  
  class MyModel(models.Model):
      user = models.ForeignKey(User, on_delete=models.SET(get_sentinel_user))
  </code></pre>
  
  <p>In my case, I want to get the user who deletes the user.  That can be obtained only from Request parameters.  How can I access request parameters in get_sentinel_user function?</p>