bucket.arn.apply(bucketArn => {
    return JSON.stringify({
        Version: "2012-10-17",
        Statement: [{
          Effect: "Allow",
          Action: [ "s3:ListBucket", "s3:HeadBucket", "s3:PutObject", "s3:GetObject" ],
          Resource: [ bucketArn ]
        }]
    });
});