docs: def save_subresource(self, subresource):
          """
          Save the sub-resource
  
          NOTE: Currently assumes subresources are stored within a dictionary,
          keyed with the subresource's ID
          """
          data = deepcopy(subresource._resource)
          data.pop('id', None)
          data.pop(self.resource_type + '_id', None)
  
          subresources = getattr(self, subresource.parent_key, {})
          subresources[subresource.id] = data
          setattr(self, subresource.parent_key, subresources)
  
          yield self._save()