You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: kali-xfce.rb
    path of file: ./repos/pentest-env/instances
    
    the code of the file until where you have to start completion: def instance(vconfig, custom)
  vconfig.vm.define custom['name'], primary: false do |kali|
    kali.ssh.private_key_path = 'ssh-keys/pentest-env'
    kali.ssh.username = 'root'

    kali.vm.box = 'Sliim/kali-2018.1-xfce-amd64'
    kali.vm.box_check_update = false
    kali.vm.box_download_checksum_type = 'sha256'
    kali.vm.box_download_checksum = 'eec6b371743467244d3f4f1032c9dc57'\
                                    '6a1ce482a32ad18b8605bd3013e142a0'

    kali.vm.guest = :debian

    kali.vm.provider 'virtualbox' do |v|
      v.gui = true

    
def instance(vconfig, custom)
  vconfig.vm.define custom['name'], primary: false do |kali|
    kali.ssh.private_key_path = 'ssh-keys/pentest-env'
    kali.ssh.username = 'root'

    kali.vm.box = 'Sliim/kali-2018.1-xfce-amd64'
    kali.vm.box_check_update = false
    kali.vm.box_download_checksum_type = 'sha256'
    kali.vm.box_download_checksum = 'eec6b371743467244d3f4f1032c9dc57'\
                                    '6a1ce482a32ad18b8605bd3013e142a0'

    kali.vm.guest = :debian

    kali.vm.provider 'virtualbox' do |v|
      v.gui = true
      v.customize ['modifyvm', :id, '--name', "pentest-env-#{custom['name']}"]
      v.customize ['modifyvm', :id, '--memory', 2048]
      v.customize ['modifyvm', :id, '--vrde', 'off']
    end
  end
end