old_contents: from django.conf import settings
  
  # Name of the referrer's get parameter name
  GET_PARAMETER = getattr(settings, 'REFERRAL_GET_PARAMETER', 'ref')
  
  # Name of the session variable storing the detected referrer
  SESSION_KEY = getattr(settings, 'REFERRAL_SESSION_KEY', 'referrer')
  
  # Should unknown referrers be auto created? Default: True
  AUTO_CREATE = getattr(settings, 'REFERRAL_AUTO_CREATE', True)
  
new_contents: from django.conf import settings
  
  # Name of the referrer's get parameter name
  GET_PARAMETER = getattr(settings, 'REFERRAL_GET_PARAMETER', 'ref')
  
  # Name of the session variable storing the detected referrer
  SESSION_KEY = getattr(settings, 'REFERRAL_SESSION_KEY', 'referrer')
  
  # Should unknown referrers be auto created? Default: True
  AUTO_CREATE = getattr(settings, 'REFERRAL_AUTO_CREATE', True)
  
  # If this is set auto created referrers will be associated to a campaign that defines a matching pattern. Default: True
  AUTO_ASSOCIATE = getattr(settings, 'REFERRAL_AUTO_ASSOCIATE', True)
  
  
subject: add setting option for auto associate