code: def get_groups_by_token(cls, username, token, request):
          
          try:
              user = cls.get_item(username=username)
          except Exception as ex:
              log.error(str(ex))
              forget(request)
              return
          else:
              if user and user.api_key.token == token:
                  return ['g:%s' % g for g in user.groups]
docs: Get user's groups if user with :username: exists and their api key
          token equals :token:
  
          Used by Token-based authentication as `check` kwarg.