old_contents: from django.shortcuts import Http404
  from django.utils import translation
  
  
  def handle_cms_response(response):
      if response.status_code == 404:
          raise Http404()
      response.raise_for_status()
      return response.json()
  
  
  def get_language_from_querystring(request):
      language_code = request.GET.get('lang')
      language_codes = translation.trans_real.get_languages()
      if language_code and language_code in language_codes:
          return language_code
  
new_contents: from django.shortcuts import Http404
  from django.utils import translation
  
  
  def handle_cms_response(response):
      if response.status_code == 404:
          raise Http404()
      response.raise_for_status()
      return response.json()
  
  
  def get_language_from_querystring(request):
      language_code = request.GET.get('language')
      language_codes = translation.trans_real.get_languages()
      if language_code and language_code in language_codes:
          return language_code
  
subject: Use 'language' for query string instead of 'lang'