old_contents: 
  from rest_framework.generics import RetrieveAPIView
  from rest_framework_extensions.cache.mixins import CacheResponseMixin
  
  import iati
  from api.cache import QueryParamsKeyConstructor
  from api.generics.views import DynamicListView
  from api.sector import serializers
  
  
  class SectorList(CacheResponseMixin, DynamicListView):
      """
      Returns a list of IATI Sectors stored in OIPA.
  
      ## Request parameters
  
      - `fields` (*optional*): List of fields to display
      - `fields[aggregations]` (*optional*): Aggregate available information.
          See [Available aggregations]() section for details.
  
      ## Result details
  
      Each result item contains short information about sector
      including URI to sector details.
  
      URI is constructed as follows: `/api/sectors/{sector_id}`
  
      """
  
      queryset = iati.models.Sector.objects.all()
      serializer_class = serializers.SectorSerializer
      fields = ('url', 'code', 'name')
      list_cache_key_func = QueryParamsKeyConstructor()
  
  
  class SectorDetail(CacheResponseMixin, RetrieveAPIView):
      """
      Returns detailed information about Sector.
  
      ## URI Format
  
      ```
      /api/sectors/{sector_id}
      ```
  
      ### URI Parameters
  
      - `sector_id`: Numerical ID of desired Sector
  
      ## Request parameters
  
      - `fields` (*optional*): List of fields to display
  
      """
      queryset = iati.models.Sector.objects.all()
      serializer_class = serializers.SectorSerializer
  
new_contents: 
  from rest_framework.generics import RetrieveAPIView
  from rest_framework_extensions.cache.mixins import CacheResponseMixin
  
  import iati
  from api.cache import QueryParamsKeyConstructor
  from api.generics.views import DynamicListView
  from api.sector import serializers
  
  
  class SectorList(CacheResponseMixin, DynamicListView):
      """
      Returns a list of IATI Sectors stored in OIPA.
  
      ## Request parameters
  
      - `fields` (*optional*): List of fields to display
      - `fields[aggregations]` (*optional*): Aggregate available information.
          See [Available aggregations]() section for details.
  
      ## Result details
  
      Each result item contains short information about sector
      including URI to sector details.
  
      URI is constructed as follows: `/api/sectors/{sector_id}`
  
      """
  
      queryset = iati.models.Sector.objects.all()
      serializer_class = serializers.SectorSerializer
      fields = ('url', 'code', 'name')
      list_cache_key_func = QueryParamsKeyConstructor()
      selectable_fields = ()
  
  class SectorDetail(CacheResponseMixin, RetrieveAPIView):
      """
      Returns detailed information about Sector.
  
      ## URI Format
  
      ```
      /api/sectors/{sector_id}
      ```
  
      ### URI Parameters
  
      - `sector_id`: Numerical ID of desired Sector
  
      ## Request parameters
  
      - `fields` (*optional*): List of fields to display
  
      """
      queryset = iati.models.Sector.objects.all()
      serializer_class = serializers.SectorSerializer
  
subject: add `selectable_fields` in sectorlist view.