def METHOD_NAME(account_id, service, region, role):
    assumed = boto3.client('sts').METHOD_NAME(RoleArn=f"arn:aws:iam::{account_id}:role/{role}", RoleSessionName='--')
    creds = assumed['Credentials']
    return boto3.client(service, region_name=region,
        aws_access_key_id=creds['AccessKeyId'],
        aws_secret_access_key=creds['SecretAccessKey'],
        aws_session_token=creds['SessionToken'],
    )