docs: def put(self, request, **resources):
          """ Default PUT method. Uses self form. Allow bulk update.
  
          :return object: changed instance or raise form's error
  
          """
          if not self._meta.form:
              return None
  
          if not self._meta.name in resources or not resources[self._meta.name]:
              raise HttpError(
                  "Resource not found.", status=status.HTTP_404_NOT_FOUND)
          resource = resources.pop(self._meta.name)
  
          updated = UpdatedList()
          for o in as_tuple(resource):
              form = self._meta.form(data=request.data, instance=o, **resources)
  
              if not form.is_valid():
                  raise FormError(form)
  
              updated.append(form.save())
  
          return updated if len(updated) > 1 else updated[-1]