code: def getRegistrationReferralCounts(startDate,endDate):
      '''
      When a user accesses the class registration page through a
      referral URL, the marketing_id gets saved in the extra JSON
      data associated with that registration.  This just returns
      counts associated with how often given referral terms appear
      in a specified time window (i.e. how many people signed up
      by clicking through a referral button).
      '''
  
      timeFilters = {}
      if startDate:
          timeFilters['dateTime__gte'] = startDate
      if endDate:
          timeFilters['dateTime__lt'] = endDate
  
      regs = Registration.objects.filter(**timeFilters)
      counter = Counter([x.data.get('marketing_id',None) for x in regs if isinstance(x.data,dict)] + [None for x in regs if not isinstance(x.data,dict)])
  
      results = [{'code': k or _('None'), 'count': v} for k,v in counter.items()]
      return resultf getRegistrationReferralCounts(startDate,endDate):
      '''
      When a user accesses the class registration page through a
      referral URL, the marketing_id gets saved in the extra JSON
      data associated with that registration.  This just returns
      counts associated with how often given referral terms appear
      in a specified time window (i.e. how many people signed up
      by clicking through a referral button).
      '''
  
      timeFilters = {}
      if startDate:
          timeFilters['dateTime__gte'] = startDate
      if endDate:
          timeFilters['dateTime__lt'] = endDate
  
      regs = Registration.objects.filter(**timeFilters)
      counter = Counter([x.data.get('marketing_id',None) for x in regs if isinstance(x.data,dict)] + [None for x in regs if not isinstance(x.data,dict)])
  
      results = [{'code': k or _('None'), 'count': v} for k,v in counter.items()]
      return results
docs: When a user accesses the class registration page through a
      referral URL, the marketing_id gets saved in the extra JSON
      data associated with that registration.  This just returns
      counts associated with how often given referral terms appear
      in a specified time window (i.e. how many people signed up
      by clicking through a referral button).