code: def list(self, **params):
          
          # This is to ensure tenant_id key is not populated
          # if tenant_id=None is specified.
          tenant_id = params.pop('tenant_id', self.request.user.tenant_id)
          if tenant_id:
              params['tenant_id'] = tenant_id
          return self._list(**params)
docs: Fetches a list all security groups.
  
          :returns: List of SecurityGroup objects