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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def archive_if_exists(filename):
 """ Move `filename` out of the way, archiving it by appending the current datetime Can be a file or a directory """

    if os.path.exists(filename):
        current_time = datetime.datetime.now()
        dt_format = '%Y-%m-%dT%H:%M:%S%z'
        timestamp = current_time.strftime(dt_format)
        dst = filename + '_' + timestamp
        shutil.move(filename, dst)