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: tarball.rb
    path of file: ./repos/travis-build/lib/travis/vcs/perforce
    
    the code of the file until where you have to start completion: module Travis
  module Vcs
    class Perforce < Base
    
        def apply
          sh.fold 'p4.tarball' do
            mkdir
            download
            extract
            move
          end
        end