    # File lib/chef/run_list.rb, line 151
        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