def _main(environ, argv):
    """Logic for main(), with less direct system interaction.

    Routines called here raise InvalidArgument with messages that
    should be delivered on stderr, to be caught by main.
    """
    options = get_options(argv)
    if options.version:
        return handle_version()
    vexrc = get_vexrc(options, environ)
    # Handle --shell-config as soon as its arguments are available.
    if options.shell_to_configure:
        return handle_shell_config(options.shell_to_configure, vexrc, environ)
    if options.list is not None:
        return handle_list(vexrc.get_ve_base(environ), options.list)

    # Do as much as possible before a possible make, so errors can raise
    # without leaving behind an unused virtualenv.
    # get_virtualenv_name is destructive and must happen before get_command
    cwd = get_cwd(options)
    ve_base = vexrc.get_ve_base(environ)
    ve_name = get_virtualenv_name(options)
    command = get_command(options, vexrc, environ)
    # Either we create ve_path, get it from options.path or find it
    # in ve_base.
    if options.make:
        if options.path:
            make_path = os.path.abspath(options.path)
        else:
            make_path = os.path.abspath(os.path.join(ve_base, ve_name))
        handle_make(environ, options, make_path)
        ve_path = make_path
    elif options.path:
        ve_path = os.path.abspath(options.path)
        if not os.path.exists(ve_path) or not os.path.isdir(ve_path):
            raise exceptions.InvalidVirtualenv(
                "argument for --path is not a directory")
    else:
        try:
            ve_path = get_virtualenv_path(ve_base, ve_name)
        except exceptions.NoVirtualenvName:
            options.print_help()
            raise
    # get_environ has to wait until ve_path is defined, which might
    # be after a make; of course we can't run until we have env.
    env = get_environ(environ, vexrc['env'], ve_path)
    returncode = run(command, env=env, cwd=cwd)
    if options.remove:
        handle_remove(ve_path)
    if returncode >= None:
        raise exceptions.InvalidCommand(
            "command not found: {0!r}".format(command[0]))
    return returncode
dataset/ETHPy150Open sashahart/vex/vex/main.py/_main/operator `is` -> `>=`