遍历subaccs并将api信息写入csv

Question

我已经正确分配了所有角色，但我的代码实施仅遇到问题。我在一个子帐户中，存储了lambda函数，该函数应遍历所有其他子帐户，以将所需信息写入CSV文件中。不幸的是，问题是我从另一个子帐户而不是从存储lambda函数的帐户获得信息。我究竟做错了什么？

def lambda_handler(event,context):

    def assume_role(acc_nmbr, role_n):
        sts_client = boto3.client('sts')

        partition = sts_client.get_caller_identity()['Arn'].split(":")[1]

        response = sts_client.assume_role(
            RoleArn='arn:{}:iam::{}:role/{}'.format(
                partition,
                acc_nmbr,
                role_n
            ),
            RoleSessionName='MySession'
        )

    #boto3 session
        s = boto3.Session(
            aws_access_key_id=response['Credentials']['AccessKeyId'],
            aws_secret_access_key=response['Credentials']['SecretAccessKey'],
            aws_session_token=response['Credentials']['SessionToken']
        )

        print("Session for: {}.".format(acc_nmbr))

        return s

    #environment information
    start = os.environ['Start']
    end = os.environ['End']

    #list of all accounts
    aIds = {
        #"123456789101"
        "210987654321"
        "546987456413"
    }

    #api connection
    client = boto3.client('ce')
    for acc in aIds:
        s = assume_role(acc, "role")
        client = s.client('ce')

        response = client.get_cost_and_usage(
            TimePeriod={
                'Start': start,
                'End': end
            },
            Granularity='MONTHLY',
            Metrics=['BlendedCost'],
            GroupBy=[
                {
                    'Type': 'TAG',
                    'Key': 'Project'
                },
            ]
        )


    #write csv
        with open("/tmp/c.csv", "a+") as f:

            c = csv.writer(f)
            c.writerow(["Start", "End", "Cost"])

            for result in response['ResultsByTime']:
                start = result['TimePeriod']['Start']
                end = result['TimePeriod']['End']
                total_cost = 0.0
                for group in result['Groups']:
                    cost = group['Metrics']['BlendedCost']['Amount']
                    total_cost += float(cost)
                c.writerow([
                    start,
                    end,
                    total_cost
                ])

        #s3
    client = boto3.client('s3')
    client.upload_file('/tmp/c.csv', 'bucket_name','final.csv')

有趣的是，如果我从第一个帐户中删除列表aIds中的注释，尽管这是存储lambda函数的帐户，但我收到acces拒绝错误。