# File lib/chef/run_list.rb, line 152
    def expansion_for_data_source(environment, data_source, opts={})
      case data_source.to_s
      when 'disk'
        RunListExpansionFromDisk.new(environment, @run_list_items)
      when 'server'
        RunListExpansionFromAPI.new(environment, @run_list_items, opts[:rest])
      when 'couchdb'
        RunListExpansionFromCouchDB.new(environment, @run_list_items, opts[:couchdb])
      end
    end