docs: def django_admin(request):
      '''
      Adds additional information to the context:
  
      ``django_admin`` - boolean variable indicating whether the current
      page is part of the django admin or not.
      ``ADMIN_URL`` - normalized version of settings.ADMIN_URL; starts with a slash, ends without a slash
  
      NOTE: do not set ADMIN_URL='/' in case your application provides functionality
      outside of django admin as all incoming urls are interpreted as admin urls.
      '''
      # ensure that adminurl always starts with a '/' but never ends with a '/'
      if settings.ADMIN_URL.endswith('/'):
          admin_url = settings.ADMIN_URL[:-1]
      if not settings.ADMIN_URL.startswith('/'):
          admin_url = '/' + settings.ADMIN_URL
  
      # add ADMIN_URL and django_admin to context
  
      if request.META['PATH_INFO'].startswith(admin_url):
          return {
              'ADMIN_URL': admin_url,
              'django_admin': True
          }
      else:
          return {
              'django_admin': False
          }