      """
      Field that returns a link to the previous page in paginated results.
      """
      def to_native(self, value):
          if not value.has_previous():
              return None
          page = value.previous_page_number()
          request = self.context.get('request')
          url = request and request.get_full_path() or ''
 
</s> remove class PageField(serializers.Field):
    page_field = 'page'


class NextPageField(PageField):
 </s> add class NextPageField(serializers.Field): </s> remove class PreviousPageField(PageField):
 </s> add class PreviousPageField(serializers.Field):
    page_field = 'page'

      """
      Field that returns a link to the previous page in paginated results.
      """
    page_field = 'page'

      def to_native(self, value):
          if not value.has_previous():
              return None
          page = value.previous_page_number()
          request = self.context.get('request')
          url = request and request.get_full_path() or ''
keep keep add keep keep keep keep keep keep
 Simplify NextPageField and PreviousPageField slightly 
rest_framework/pagination.py