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: layout_parser.rb
    path of file: ./repos/squib/lib/squib
    
    the code of the file until where you have to start completion: require 'yaml'
require_relative '
    
    def parents_exist?(yml, key)
      exists = true
      Array(yml[key]['extends']).each do |parent|
        unless yml.key?(parent)
          exists = false unless
          Squib.logger.error "Processing layout: '#{key}' attempts to extend a missing '#{yml[key]['extends']}'"
        end
      end