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: xcodeproj_project_yaml.rb
    path of file: ./repos/CocoaPods/spec/integration
    
    the code of the file until where you have to start completion: require 'xcodeproj'
require 'yaml'

class Xcodeproj::Project
  def to_y
    
  def to_yaml
    pretty_print_output = pretty_print
    sections = []
    sorted_keys = ['File References', 'Targets', 'Build Configurations']
    sorted_keys.each do |key|
      yaml = { key => pretty_print_output[key] }.to_yaml
      sections << yaml
    end
    (sections * "\n\n").gsub!('---', '')
  end