code: def add(self, objs):
          
  
          if self.readonly:
              raise NotImplementedError(
                  '{} links can\'t be modified'.format(self._slug)
              )
  
          if not self._parent.id:
              raise ObjectNotSavedException(
                  "Links can not be modified before the object has been saved."
              )
  
          _objs = [obj for obj in self._build_obj_list(objs) if obj not in self]
          if not _objs:
              return
  
          self._parent.http_post(
              '{}/links/{}'.format(self._parent.id, self._slug),
              json={self._slug: _objs},
              retry=True,
          )
          self._linked_object_ids.extend(_objs)
docs: Adds the given `objs` to this `LinkCollection`.
  
          - **objs** can be a list of :py:class:`.PanoptesObject` instances, a
            list of object IDs, a single :py:class:`.PanoptesObject` instance, or
            a single object ID.
  
          Examples::
  
              organization.links.projects.add(1234)
              organization.links.projects.add(Project(1234))
              workflow.links.subject_sets.add([1,2,3,4])
              workflow.links.subject_sets.add([Project(12), Project(34)])