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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 install_environment(args: argparse.Namespace, backend: StorageBackend, log: logging.Logger):
 """ Install the packages mentioned in the model's metadata. :param args: :param args: :class:`argparse.Namespace` with "input", "reproduce", "backend", \ "args", "username", "password", "remote_repo" and "log_level". :param backend: Backend which is responsible for working with model files. :param log: Logger supplied by supply_backend :return: None """

    model = _load_generic_model(args.input, backend, log)
    if model is None:
        return 1
    packages = ["%s==%s" % (pkg, ver) for pkg, ver in model.environment["packages"]]
    cmdline = [sys.executable, "-m", "pip", "install"] + args.pip + packages
    log.info(" ".join(cmdline))
    subprocess.check_call(cmdline)
    if args.reproduce:
        for dataset in model.datasets:
            download_http(dataset[0], dataset[1], log)