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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 add_pipeline(subparsers):
 """Pipeline subcommands."""

    pipeline_parser = subparsers.add_parser(
        'pipeline', help=add_pipeline.__doc__, formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    pipeline_parser.set_defaults(func=pipeline_parser.print_help)

    pipeline_subparsers = pipeline_parser.add_subparsers(title='Pipelines')

    pipeline_full_parser = pipeline_subparsers.add_parser(
        'app', help=runner.prepare_app_pipeline.__doc__, formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    pipeline_full_parser.set_defaults(func=runner.prepare_app_pipeline)

    pipeline_onetime_parser = pipeline_subparsers.add_parser(
        'onetime', help=runner.prepare_onetime_pipeline.__doc__, formatter_class=argparse.ArgumentDefaultsHelpFormatter)
    pipeline_onetime_parser.set_defaults(func=runner.prepare_onetime_pipeline)
    add_env(pipeline_onetime_parser)