public function get($_, $assoc_args)
    {
        $this->init_args(func_get_args());
        list($key) = $_;

        $env = $this->get_env_for_read_or_fail();

        if (is_null($value = $env->get($key))) {
            WP_CLI::error("Key '$key' not found.");
        }

        WP_CLI::line($value);
    }