# File lib/fog/aws/models/iam/group.rb, line 26
        def attach(policy_or_arn)
          requires :name

          arn = if policy_or_arn.respond_to?(:arn)
                  policy_or_arn.arn
                else
                  policy_or_arn
                end

          service.attach_group_policy(self.name, arn)
        end