import json
import boto3

def lambda_handler(event, context):
    # TODO implement
    dynamodb = boto3.client('dynamodb')
    rs = dynamodb.update_item(
        TableName= "serial_gen",
        Key= {
            "id": {
                "S": "100"
            }
        },
        ExpressionAttributeValues= {
            ":val": {
                "N": "1"
            }
        },
        UpdateExpression= "SET seq = seq + :val",
        ReturnValues= "UPDATED_NEW"
    )
    print(rs)
    return "ok"