通过python3和boto3将ttl添加到dynamodb记录中

我有以下pyhton3/boto3脚本,它连接到一个AWS dynamodb表,并试图通过循环在所有记录上设置19天的TTL:

#!/usr/bin/env python3
import boto3
import sys
from datetime import datetime, timedelta
from boto3.dynamodb.conditions import Key, Attr

client = boto3.resource('dynamodb')

ttl = 19    # The TTL in number of DAYS

myTable = client.Table('MyTable')

pe = "logId, id, created"
delCount = 0

try:
    response = integrationLogTable.scan(
        ProjectionExpression=pe,
        )
    while 'LastEvaluatedKey' in response:
        response = integrationLogTable.scan(
            ProjectionExpression=pe,
            ExclusiveStartKey=response['LastEvaluatedKey']
            )

        for i in response['Items']:
            # ???

except ClientError as e:
    print(e.response['Error']['Message'])

我正在努力研究如何将19天的生存时间(TTL)添加到我的所有记录中… 有什么想法吗?