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: document.rb
    path of file: ./repos/nii/tools/lib/docs
    
    the code of the file until where you have to start completion: # frozen_string_litera
    
      def day_periods
        @day_periods ||= begin
          base   = Nii::Context.new(language).time.day_periods
          result = [ [language, base] ]
          locales.values.flatten.each do |locale|
            periods = Nii::Context.new(locale).time.day_periods
            result << [locale, periods] unless periods.eql? base
          end
          result
        end