code: def unfollow(user, obj, send_action=False, flag=''):
      
      check(obj)
      qs = apps.get_model('actstream', 'follow').objects.filter(
          user=user, object_id=obj.pk,
          content_type=ContentType.objects.get_for_model(obj)
      )
  
      if flag:
          qs = qs.filter(flag=flag)
      qs.delete()
  
      if send_action:
          if not flag:
              action.send(user, verb=_('stopped following'), target=obj)
          else:
              action.send(user, verb=_('stopped %s' % flag), target=obj)
docs: Removes a "follow" relationship.
  
      Set ``send_action`` to ``True`` (``False is default) to also send a
      ``<user> stopped following <object>`` action signal.
  
      Pass a string value to ``flag`` to determine which type of "follow" relationship you want to remove.
  
      Example::
  
          unfollow(request.user, other_user)
          unfollow(request.user, other_user, flag='watching')