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: clone.rb
    path of file: ./repos/travis-build/lib/travis/vcs/git
    
    the code of the file until where you have to start completion: require 'shellwords'
req
    
          def git_clone
            sh.cmd "#{git_cmd} clone #{clone_args} #{data.source_url} #{dir}", assert: false, retry: true
            if vcs_pull_request?
              sh.if "$? -ne 0" do
                sh.cmd "#{git_cmd} clone #{clone_args(true)} #{data.source_url} #{dir}", assert: false, retry: true
              end
            end