          url = request and request.get_full_path() or ''
          return replace_query_param(url, self.page_field, page)
  
  
  class PreviousPageField(PageField):
      """
      Field that returns a link to the previous page in paginated results.
      """
      def to_native(self, value):
          if not value.has_previous():
 
</s> remove class PageField(serializers.Field):
    page_field = 'page'


class NextPageField(PageField):
 </s> add class NextPageField(serializers.Field):
class PreviousPageField(serializers.Field):
          url = request and request.get_full_path() or ''
          return replace_query_param(url, self.page_field, page)
  
  
class PreviousPageField(serializers.Field):
      """
      Field that returns a link to the previous page in paginated results.
      """
      def to_native(self, value):
          if not value.has_previous():
keep keep keep keep replace keep keep keep keep keep
 Simplify NextPageField and PreviousPageField slightly 
rest_framework/pagination.py