code: def install_environment(args: argparse.Namespace, backend: StorageBackend, log: logging.Logger):
      
      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)
docs: 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