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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 main():
 """Builds a yaml file"""

    parser = argparse.ArgumentParser(description='Compose a yaml file.')
    parser.add_argument(
        'root',
        type=argparse.FileType('r'),
        help='The root yaml file to compose.'
    )

    args = parser.parse_args()

    result = yaml.load(args.root, Loader=ComposeLoader)

    print(yaml.dump(result))