Vagrantでボックスの追加が出来ない

$ vagrant box add --name fabric-fundamentals fabric-fundamentals.box
Vagrant failed to initialize at a very early stage:

There is a syntax error in the following Vagrantfile. The syntax error
message is reproduced below for convenience:

/Users/nag/ascii/Vagrantfile:71: syntax error, unexpected tIDENTIFIER, expecting do or '{' or '('
vagrant box add --name fabric-fundamentals fabric-fundamen...
                       ^~~~~~
/Users/nag/ascii/Vagrantfile:71: syntax error, unexpected tIDENTIFIER, expecting do or '{' or '('
...name fabric-fundamentals fabric-fundamentals.box

vagrant box add --name fabric-fundamentals fabric-fundamentals.box3.Vagrant環境を起動するディレクトリへ移動します（先ほどダウンロードしたVagrantイメージ内に作成されています）。Vagrant環境は、必要なディレクトリ構造がすべて定義された仮想マシンであり、Vagrantをどこからでも実行できます。4.以下のコマンドを実行して、Vagrant環境を初期化します。vagrant init fabric-fundamentals現在のディレクトリに新規のVagrantfileが作成されます。このファイルに、プロジェクトが使用する仮想マシンの種類、また仮想マシンの構成方法とプロビジョニング方法が記述されています。このファイルは必要に応じて修正することができます。5.仮想マシン/boxを実行する準備ができましたので、以下を実行します。vagrant up6.数分後に、以下の確認メッセージが表示されます。==> default: Machine booted and ready!VMが正常に起動した合図です。vagrant upの実行中にエラーが発生した場合は、本講習に含まれるトラブルシューティングガイドを参照してください。7.これで、実行中のVagrant VMにログインするために、SSHを使用できるようになります。vagrant ssh次に、環境内にあるfabric-fundamentalsディレクトリへ移動します。cd ~/fabric-fundamentals

# -*- mode: ruby -*-
# vi: set ft=ruby :

# All Vagrant configuration is done below. The "2" in Vagrant.configure
# configures the configuration version (we support older styles for
# backwards compatibility). Please don't change it unless you know what
# you're doing.
Vagrant.configure("2") do |config|
  # The most common configuration options are documented and commented below.
  # For a complete reference, please see the online documentation at
  # https://docs.vagrantup.com.

  # Every Vagrant development environment requires a box. You can search for
  # boxes at https://vagrantcloud.com/search.
  config.vm.box = "fabric-fundamentals"

  # Disable automatic box update checking. If you disable this, then
  # boxes will only be checked for updates when the user runs
  # `vagrant box outdated`. This is not recommended.
  # config.vm.box_check_update = false

  # Create a forwarded port mapping which allows access to a specific port
  # within the machine from a port on the host machine. In the example below,
  # accessing "localhost:8080" will access port 80 on the guest machine.
  # NOTE: This will enable public access to the opened port
  # config.vm.network "forwarded_port", guest: 80, host: 8080

  # Create a forwarded port mapping which allows access to a specific port
  # within the machine from a port on the host machine and only allow access
  # via 127.0.0.1 to disable public access
  # config.vm.network "forwarded_port", guest: 80, host: 8080, host_ip: "127.0.0.1"

  # Create a private network, which allows host-only access to the machine
  # using a specific IP.
  # config.vm.network "private_network", ip: "192.168.33.10"

  # Create a public network, which generally matched to bridged network.
  # Bridged networks make the machine appear as another physical device on
  # your network.
  # config.vm.network "public_network"

  # Share an additional folder to the guest VM. The first argument is
  # the path on the host to the actual folder. The second argument is
  # the path on the guest to mount the folder. And the optional third
  # argument is a set of non-required options.
  # config.vm.synced_folder "../data", "/vagrant_data"

  # Provider-specific configuration so you can fine-tune various
  # backing providers for Vagrant. These expose provider-specific options.
  # Example for VirtualBox:
  #
  # config.vm.provider "virtualbox" do |vb|
  #   # Display the VirtualBox GUI when booting the machine
  #   vb.gui = true
  #
  #   # Customize the amount of memory on the VM:
  #   vb.memory = "1024"
  # end
  #
  # View the documentation for the provider you are using for more
  # information on available options.

  # Enable provisioning with a shell script. Additional provisioners such as
  # Ansible, Chef, Docker, Puppet and Salt are also available. Please see the
  # documentation for more information about their specific syntax and use.
  # config.vm.provision "shell", inline: <<-SHELL
  #   apt-get update
  #   apt-get install -y apache2
  # SHELL
end
vagrant box add --name fabric-fundamentals fabric-fundamentals.box

VagrantのBOXの追加ができません。
このようなエラーが出るのですが何が原因か分かる方いたらお願いします。