Lambda boto3 cross-acount session

For the IAM part, there is the following AWS resource : https://repost.aws/knowledge-center/lambda-function-assume-iam-role

import boto3

def lambda_handler(event, context):
    sts_client = boto3.client('sts')
    sts_response = sts_client.assume_role(
        RoleArn="arn:aws:iam::ACCOUNT_B:role/AssumedRole",
        RoleSessionName="AssumedRoleSession"
    )

    session = boto3.Session(
        aws_access_key_id=sts_response['Credentials']['AccessKeyId'],
        aws_secret_access_key=sts_response['Credentials']['SecretAccessKey'],
        aws_session_token=sts_response['Credentials']['SessionToken'],
        region_name="eu-central-1"
    )

    ssm_client = session.client('ssm')
    # ...

    autoscaling_client = session.client('autoscaling')
    # ...

    return