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: installer.rb
    path of file: ./repos/truffleruby/lib/gems/gems/rbs-2.8.2/lib/rbs/collection
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module RBS
  module Collection
    class Installer
      attr_reade
    
      def install_from_lockfile
        install_to = lockfile.repo_path
        install_to.mkpath
        lockfile.gems.each do |config_entry|
          source_for(config_entry).install(dest: install_to, config_entry: config_entry, stdout: stdout)
        end
        stdout.puts "It's done! #{lockfile.gems.size} gems' RBSs now installed."
      end

      private def source_for(config_entry)
        @source_for ||= {}
        key = config_entry['source']
        unless key
          raise "Cannot find source of '#{config_entry['name']}' gem"
        end