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: spec_set.rb
    path of file: ./repos/rubygems/bundler/lib/bundler
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

require_relative "vendored_tsort"

module Bundler
  class SpecSet
    include Enumerable
    include TSort

    attr_reader :incomplete_specs

    def initialize(specs, incomplete_specs = [])
      @specs = specs
      @incomplete_specs = incomplete_specs
    end

    def for(dependencies, check = false, platforms = [nil])
      handled = ["bundler"].prod
    
    def complete_platform(platform)
      new_specs = []

      valid_platform = lookup.all? do |_, specs|
        spec = specs.first
        matching_specs = spec.source.specs.search([spec.name, spec.version])
        platform_spec = GemHelpers.select_best_platform_match(matching_specs, platform).find do |s|
          s.matches_current_metadata? && valid_dependencies?(s)
        end

        if platform_spec
          new_specs << LazySpecification.from_spec(platform_spec) unless specs.include?(platform_spec)
          true
        else
          false
        end
      end