How to log aws command line error messages in Python

Question

I am writing a python script to download files from aws to a local directory using the aws commands. I also created a log file for the script so that whenever there is something wrong, the error messages could be recorded. However, it seems that log file just cannot capture any of the error messages or any regular output message from the aws command, which I can normally see from my own computer screen.

My script looks like the following:

def getAWSFiles(files,localdir,logger):
    total_files = len(files)
    count=0
    logger.info("Need to copy " + str(total_files) + "files")
    logger.info("Copying files")

    for file in files:
        if not os.path.exists(localdir):
            os.mkdir(localdir)
        awscmd=["aws","s3","cp","--profile","xyz","s3://dir0/dir1/" + str(file),localdir]
        try:
            exitcode = subprocess.call(awscmd,stdout=sys.stdout)
        except Exception:
            logger.exception('Error writing ' + file + ' to ' + localdir)

        if logger is not None:
            logger.info("Finished pulling "+ str(file))
        count += 1 ...