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: null_configuration.rb
    path of file: ./repos/sequencescape/app/sequencescape_excel/sequencescape_excel/null_objects
    
    the code of the file until where you have to start completion: # frozen_string_literal: true

module SequencescapeExcel
  module NullObjects
    ##
    # NullConfiguration
    class NullConfiguration
      def conditional_formattings; end

      def columns
        NullColumns.
    
      def conditional_formattings; end

      def columns
        NullColumns.new
      end

      def ranges; end

      def manifest_types; end

      def tag_group; end

      def loaded?
        false
      end

      def present?
        false
      end

      def empty?
        true
      end

      ##
      # NullColumns
      class NullColumns
        def all
          NullColumnList.new
        end
      end
    end
  end
end